Merge branch 'master' of git://github.com/rails/rails

92 files changed, 4447 insertions, 3221 deletions

diff --git a/activerecord/lib/active_record/aggregations.rb b/activerecord/lib/active_record/aggregations.rb
index 81ddbba51e..5a8addc4e4 100644
--- a/activerecord/lib/active_record/aggregations.rb
+++ b/activerecord/lib/active_record/aggregations.rb
@@ -172,8 +172,8 @@ module ActiveRecord
       #   with this option.
       # * <tt>:mapping</tt> - Specifies the mapping of entity attributes to attributes of the value
       #   object. Each mapping is represented as an array where the first item is the name of the
-      #   entity attribute and the second item is the name the attribute in the value object. The
-      #   order in which mappings are defined determine the order in which attributes are sent to the
+      #   entity attribute and the second item is the name of the attribute in the value object. The
+      #   order in which mappings are defined determines the order in which attributes are sent to the
       #   value class constructor.
       # * <tt>:allow_nil</tt> - Specifies that the value object will not be instantiated when all mapped
       #   attributes are +nil+. Setting the value object to +nil+ has the effect of writing +nil+ to all
@@ -191,7 +191,8 @@ module ActiveRecord
       #
       # Option examples:
       #   composed_of :temperature, :mapping => %w(reading celsius)
-      #   composed_of :balance, :class_name => "Money", :mapping => %w(balance amount), :converter => Proc.new { |balance| balance.to_money }
+      #   composed_of :balance, :class_name => "Money", :mapping => %w(balance amount),
+      #                         :converter => Proc.new { |balance| balance.to_money }
       #   composed_of :address, :mapping => [ %w(address_street street), %w(address_city city) ]
       #   composed_of :gps_location
       #   composed_of :gps_location, :allow_nil => true
diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index 0952ea2829..0efa111d12 100644
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -70,7 +70,7 @@ module ActiveRecord
     end
   end
 
-  class HasManyThroughNestedAssociationsAreReadonly < ActiveRecordError #:nodoc
+  class HasManyThroughNestedAssociationsAreReadonly < ActiveRecordError #:nodoc:
     def initialize(owner, reflection)
       super("Cannot modify association '#{owner.class.name}##{reflection.name}' because it goes through more than one other association.")
     end
@@ -196,6 +196,26 @@ module ActiveRecord
     # * <tt>Project#categories.empty?, Project#categories.size, Project#categories, Project#categories<<(category1),</tt>
     #   <tt>Project#categories.delete(category1)</tt>
     #
+    # === Overriding generated methods
+    #
+    # Association methods are generated in a module that is included into the model class,
+    # which allows you to easily override with your own methods and call the original
+    # generated method with +super+. For example:
+    #
+    #   class Car < ActiveRecord::Base
+    #     belongs_to :owner
+    #     belongs_to :old_owner
+    #     def owner=(new_owner)
+    #       self.old_owner = self.owner
+    #       super
+    #     end
+    #   end
+    #
+    # If your model class is <tt>Project</tt>, the module is
+    # named <tt>Project::GeneratedFeatureMethods</tt>. The GeneratedFeatureMethods module is
+    # included in the model class immediately after the (anonymous) generated attributes methods
+    # module, meaning an association will override the methods for an attribute with the same name.
+    #
     # === A word of warning
     #
     # Don't create associations that have the same name as instance methods of
@@ -1165,7 +1185,7 @@ module ActiveRecord
       #   has_many :subscribers, :through => :subscriptions, :source => :user
       #   has_many :subscribers, :class_name => "Person", :finder_sql => Proc.new {
       #       %Q{
-      #         SELECT DISTINCT people.*
+      #         SELECT DISTINCT *
       #         FROM people p, post_subscriptions ps
       #         WHERE ps.post_id = #{id} AND ps.person_id = p.id
       #         ORDER BY p.first_name
@@ -1424,18 +1444,18 @@ module ActiveRecord
       # join table with a migration such as this:
       #
       #   class CreateDevelopersProjectsJoinTable < ActiveRecord::Migration
-      #     def self.up
+      #     def change
       #       create_table :developers_projects, :id => false do |t|
       #         t.integer :developer_id
       #         t.integer :project_id
       #       end
       #     end
-      #
-      #     def self.down
-      #       drop_table :developers_projects
-      #     end
       #   end
       #
+      # It's also a good idea to add indexes to each of those columns to speed up the joins process.
+      # However, in MySQL it is advised to add a compound index for both of the columns as MySQL only
+      # uses one index per table during the lookup.
+      #
       # Adds the following methods for retrieval and query:
       #
       # [collection(force_reload = false)]
diff --git a/activerecord/lib/active_record/associations/association.rb b/activerecord/lib/active_record/associations/association.rb
index d1e3ff8e38..7887d59aad 100644
--- a/activerecord/lib/active_record/associations/association.rb
+++ b/activerecord/lib/active_record/associations/association.rb
@@ -231,10 +231,7 @@ module ActiveRecord
 
         def build_record(attributes, options)
           reflection.build_association(attributes, options) do |record|
-            record.assign_attributes(
-              create_scope.except(*record.changed),
-              :without_protection => true
-            )
+            record.assign_attributes(create_scope.except(*record.changed), :without_protection => true)
           end
         end
     end
diff --git a/activerecord/lib/active_record/associations/association_scope.rb b/activerecord/lib/active_record/associations/association_scope.rb
index 6cc401e6cc..090f690f0d 100644
--- a/activerecord/lib/active_record/associations/association_scope.rb
+++ b/activerecord/lib/active_record/associations/association_scope.rb
@@ -20,31 +20,19 @@ module ActiveRecord
         # It's okay to just apply all these like this. The options will only be present if the
         # association supports that option; this is enforced by the association builder.
         scope = scope.apply_finder_options(options.slice(
-          :readonly, :include, :order, :limit, :joins, :group, :having, :offset))
+          :readonly, :include, :eager_load, :order, :limit, :joins, :group, :having, :offset, :select))
 
         if options[:through] && !options[:include]
           scope = scope.includes(source_options[:include])
         end
 
-        if select = select_value
-          scope = scope.select(select)
-        end
+        scope = scope.uniq if options[:uniq]
 
         add_constraints(scope)
       end
 
       private
 
-      def select_value
-        select_value = options[:select]
-
-        if reflection.collection?
-          select_value ||= options[:uniq] && "DISTINCT #{reflection.quoted_table_name}.*"
-        end
-
-        select_value
-      end
-
       def add_constraints(scope)
         tables = construct_tables
 
diff --git a/activerecord/lib/active_record/associations/builder/association.rb b/activerecord/lib/active_record/associations/builder/association.rb
index 96fca97440..776f0d0469 100644
--- a/activerecord/lib/active_record/associations/builder/association.rb
+++ b/activerecord/lib/active_record/associations/builder/association.rb
@@ -1,7 +1,7 @@
 module ActiveRecord::Associations::Builder
   class Association #:nodoc:
     class_attribute :valid_options
-    self.valid_options = [:class_name, :foreign_key, :select, :conditions, :include, :extend, :readonly, :validate]
+    self.valid_options = [:class_name, :foreign_key, :select, :conditions, :include, :eager_load, :extend, :readonly, :validate]
 
     # Set by subclasses
     class_attribute :macro
@@ -16,6 +16,10 @@ module ActiveRecord::Associations::Builder
       @model, @name, @options = model, name, options
     end
 
+    def mixin
+      @model.generated_feature_methods
+    end
+
     def build
       validate_options
       reflection = model.create_reflection(self.class.macro, name, options, model)
@@ -36,16 +40,14 @@ module ActiveRecord::Associations::Builder
 
       def define_readers
         name = self.name
-
-        model.redefine_method(name) do |*params|
+        mixin.redefine_method(name) do |*params|
           association(name).reader(*params)
         end
       end
 
       def define_writers
         name = self.name
-
-        model.redefine_method("#{name}=") do |value|
+        mixin.redefine_method("#{name}=") do |value|
           association(name).writer(value)
         end
       end
diff --git a/activerecord/lib/active_record/associations/builder/belongs_to.rb b/activerecord/lib/active_record/associations/builder/belongs_to.rb
index f6d26840c2..1759a41d93 100644
--- a/activerecord/lib/active_record/associations/builder/belongs_to.rb
+++ b/activerecord/lib/active_record/associations/builder/belongs_to.rb
@@ -25,14 +25,14 @@ module ActiveRecord::Associations::Builder
         name         = self.name
 
         method_name = "belongs_to_counter_cache_after_create_for_#{name}"
-        model.redefine_method(method_name) do
+        mixin.redefine_method(method_name) do
           record = send(name)
           record.class.increment_counter(cache_column, record.id) unless record.nil?
         end
         model.after_create(method_name)
 
         method_name = "belongs_to_counter_cache_before_destroy_for_#{name}"
-        model.redefine_method(method_name) do
+        mixin.redefine_method(method_name) do
           record = send(name)
           record.class.decrement_counter(cache_column, record.id) unless record.nil?
         end
@@ -48,7 +48,7 @@ module ActiveRecord::Associations::Builder
         method_name = "belongs_to_touch_after_save_or_destroy_for_#{name}"
         touch       = options[:touch]
 
-        model.redefine_method(method_name) do
+        mixin.redefine_method(method_name) do
           record = send(name)
 
           unless record.nil?
diff --git a/activerecord/lib/active_record/associations/builder/collection_association.rb b/activerecord/lib/active_record/associations/builder/collection_association.rb
index f62209a226..35f9a3ae8e 100644
--- a/activerecord/lib/active_record/associations/builder/collection_association.rb
+++ b/activerecord/lib/active_record/associations/builder/collection_association.rb
@@ -58,7 +58,7 @@ module ActiveRecord::Associations::Builder
         super
 
         name = self.name
-        model.redefine_method("#{name.to_s.singularize}_ids") do
+        mixin.redefine_method("#{name.to_s.singularize}_ids") do
           association(name).ids_reader
         end
       end
@@ -67,7 +67,7 @@ module ActiveRecord::Associations::Builder
         super
 
         name = self.name
-        model.redefine_method("#{name.to_s.singularize}_ids=") do |ids|
+        mixin.redefine_method("#{name.to_s.singularize}_ids=") do |ids|
           association(name).ids_writer(ids)
         end
       end
diff --git a/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb b/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb
index 30fc44b4c2..0b634ab944 100644
--- a/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb
+++ b/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb
@@ -18,7 +18,7 @@ module ActiveRecord::Associations::Builder
         model.send(:include, Module.new {
           class_eval <<-RUBY, __FILE__, __LINE__ + 1
             def destroy_associations
-              association(#{name.to_sym.inspect}).delete_all
+              association(#{name.to_sym.inspect}).delete_all_on_destroy
               super
             end
           RUBY
diff --git a/activerecord/lib/active_record/associations/builder/has_many.rb b/activerecord/lib/active_record/associations/builder/has_many.rb
index ecbc70888f..9c24f40690 100644
--- a/activerecord/lib/active_record/associations/builder/has_many.rb
+++ b/activerecord/lib/active_record/associations/builder/has_many.rb
@@ -28,7 +28,7 @@ module ActiveRecord::Associations::Builder
 
       def define_destroy_dependency_method
         name = self.name
-        model.send(:define_method, dependency_method_name) do
+        mixin.redefine_method(dependency_method_name) do
           send(name).each do |o|
             # No point in executing the counter update since we're going to destroy the parent anyway
             counter_method = ('belongs_to_counter_cache_before_destroy_for_' + self.class.name.downcase).to_sym
@@ -45,15 +45,21 @@ module ActiveRecord::Associations::Builder
 
       def define_delete_all_dependency_method
         name = self.name
-        model.send(:define_method, dependency_method_name) do
+        mixin.redefine_method(dependency_method_name) do
+          association(name).delete_all_on_destroy
+        end
+      end
+
+      def define_nullify_dependency_method
+        name = self.name
+        mixin.redefine_method(dependency_method_name) do
           send(name).delete_all
         end
       end
-      alias :define_nullify_dependency_method :define_delete_all_dependency_method
 
       def define_restrict_dependency_method
         name = self.name
-        model.send(:define_method, dependency_method_name) do
+        mixin.redefine_method(dependency_method_name) do
           raise ActiveRecord::DeleteRestrictionError.new(name) unless send(name).empty?
         end
       end
diff --git a/activerecord/lib/active_record/associations/builder/has_one.rb b/activerecord/lib/active_record/associations/builder/has_one.rb
index 88c0d3e90f..7a6cd3890f 100644
--- a/activerecord/lib/active_record/associations/builder/has_one.rb
+++ b/activerecord/lib/active_record/associations/builder/has_one.rb
@@ -44,18 +44,17 @@ module ActiveRecord::Associations::Builder
       end
 
       def define_destroy_dependency_method
-        model.send(:class_eval, <<-eoruby, __FILE__, __LINE__ + 1)
-          def #{dependency_method_name}
-            association(#{name.to_sym.inspect}).delete
-          end
-        eoruby
+        name = self.name
+        mixin.redefine_method(dependency_method_name) do
+          association(name).delete
+        end
       end
       alias :define_delete_dependency_method :define_destroy_dependency_method
       alias :define_nullify_dependency_method :define_destroy_dependency_method
 
       def define_restrict_dependency_method
         name = self.name
-        model.redefine_method(dependency_method_name) do
+        mixin.redefine_method(dependency_method_name) do
           raise ActiveRecord::DeleteRestrictionError.new(name) unless send(name).nil?
         end
       end
diff --git a/activerecord/lib/active_record/associations/builder/singular_association.rb b/activerecord/lib/active_record/associations/builder/singular_association.rb
index 0cbbba041a..436b6c1524 100644
--- a/activerecord/lib/active_record/associations/builder/singular_association.rb
+++ b/activerecord/lib/active_record/associations/builder/singular_association.rb
@@ -16,15 +16,15 @@ module ActiveRecord::Associations::Builder
       def define_constructors
         name = self.name
 
-        model.redefine_method("build_#{name}") do |*params, &block|
+        mixin.redefine_method("build_#{name}") do |*params, &block|
           association(name).build(*params, &block)
         end
 
-        model.redefine_method("create_#{name}") do |*params, &block|
+        mixin.redefine_method("create_#{name}") do |*params, &block|
           association(name).create(*params, &block)
         end
 
-        model.redefine_method("create_#{name}!") do |*params, &block|
+        mixin.redefine_method("create_#{name}!") do |*params, &block|
           association(name).create!(*params, &block)
         end
       end
diff --git a/activerecord/lib/active_record/associations/collection_association.rb b/activerecord/lib/active_record/associations/collection_association.rb
index cec876149c..fe9f30bd2a 100644
--- a/activerecord/lib/active_record/associations/collection_association.rb
+++ b/activerecord/lib/active_record/associations/collection_association.rb
@@ -49,10 +49,18 @@ module ActiveRecord
           end
         else
           column  = "#{reflection.quoted_table_name}.#{reflection.association_primary_key}"
+          relation = scoped
 
-          scoped.select(column).map! do |record|
-            record.send(reflection.association_primary_key)
+          including = (relation.eager_load_values + relation.includes_values).uniq
+
+          if including.any?
+            join_dependency = ActiveRecord::Associations::JoinDependency.new(reflection.klass, including, [])
+            relation = join_dependency.join_associations.inject(relation) do |r, association|
+              association.join_relation(r)
+            end
           end
+
+          relation.uniq.pluck(column)
         end
       end
 
@@ -152,6 +160,13 @@ module ActiveRecord
         end
       end
 
+      # Called when the association is declared as :dependent => :delete_all. This is
+      # an optimised version which avoids loading the records into memory. Not really
+      # for public consumption.
+      def delete_all_on_destroy
+        scoped.delete_all
+      end
+
       # Destroy all the records from this association.
       #
       # See destroy for more info.
@@ -235,7 +250,7 @@ module ActiveRecord
       # This method is abstract in the sense that it relies on
       # +count_records+, which is a method descendants have to provide.
       def size
-        if owner.new_record? || (loaded? && !options[:uniq])
+        if !find_target? || (loaded? && !options[:uniq])
           target.size
         elsif !loaded? && options[:group]
           load_target.size
@@ -344,8 +359,12 @@ module ActiveRecord
           if options[:counter_sql]
             interpolate(options[:counter_sql])
           else
-            # replace the SELECT clause with COUNT(*), preserving any hints within /* ... */
-            interpolate(options[:finder_sql]).sub(/SELECT\b(\/\*.*?\*\/ )?(.*)\bFROM\b/im) { "SELECT #{$1}COUNT(*) FROM" }
+            # replace the SELECT clause with COUNT(SELECTS), preserving any hints within /* ... */
+            interpolate(options[:finder_sql]).sub(/SELECT\b(\/\*.*?\*\/ )?(.*)\bFROM\b/im) do
+              count_with = $2.to_s
+              count_with = '*' if count_with.blank? || count_with =~ /,/
+              "SELECT #{$1}COUNT(#{count_with}) FROM"
+            end
           end
         end
 
diff --git a/activerecord/lib/active_record/associations/collection_proxy.rb b/activerecord/lib/active_record/associations/collection_proxy.rb
index 3181ca9a32..eb320bc774 100644
--- a/activerecord/lib/active_record/associations/collection_proxy.rb
+++ b/activerecord/lib/active_record/associations/collection_proxy.rb
@@ -39,10 +39,9 @@ module ActiveRecord
       instance_methods.each { |m| undef_method m unless m.to_s =~ /^(?:nil\?|send|object_id|to_a)$|^__|^respond_to|proxy_/ }
 
       delegate :group, :order, :limit, :joins, :where, :preload, :eager_load, :includes, :from,
-               :lock, :readonly, :having, :to => :scoped
+               :lock, :readonly, :having, :pluck, :to => :scoped
 
-      delegate :target, :load_target, :loaded?, :scoped,
-               :to => :@association
+      delegate :target, :load_target, :loaded?, :to => :@association
 
       delegate :select, :find, :first, :last,
                :build, :create, :create!,
@@ -62,6 +61,13 @@ module ActiveRecord
         @association
       end
 
+      def scoped
+        association = @association
+        association.scoped.extending do
+          define_method(:proxy_association) { association }
+        end
+      end
+
       def respond_to?(name, include_private = false)
         super ||
         (load_target && target.respond_to?(name, include_private)) ||
diff --git a/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb b/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
index 1f917f58f2..a4cea99372 100644
--- a/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
+++ b/activerecord/lib/active_record/associations/has_and_belongs_to_many_association.rb
@@ -32,6 +32,10 @@ module ActiveRecord
         record
       end
 
+      # ActiveRecord::Relation#delete_all needs to support joins before we can use a
+      # SQL-only implementation.
+      alias delete_all_on_destroy delete_all
+
       private
 
         def count_records
diff --git a/activerecord/lib/active_record/associations/has_many_association.rb b/activerecord/lib/active_record/associations/has_many_association.rb
index 50ee60284c..059e6c77bc 100644
--- a/activerecord/lib/active_record/associations/has_many_association.rb
+++ b/activerecord/lib/active_record/associations/has_many_association.rb
@@ -99,6 +99,10 @@ module ActiveRecord
             end
           end
         end
+
+        def foreign_key_present?
+          owner.attribute_present?(reflection.association_primary_key)
+        end
     end
   end
 end
diff --git a/activerecord/lib/active_record/associations/has_many_through_association.rb b/activerecord/lib/active_record/associations/has_many_through_association.rb
index 2e818dca5d..9657cb081d 100644
--- a/activerecord/lib/active_record/associations/has_many_through_association.rb
+++ b/activerecord/lib/active_record/associations/has_many_through_association.rb
@@ -6,6 +6,13 @@ module ActiveRecord
     class HasManyThroughAssociation < HasManyAssociation #:nodoc:
       include ThroughAssociation
 
+      def initialize(owner, reflection)
+        super
+
+        @through_records     = {}
+        @through_association = nil
+      end
+
       # Returns the size of the collection by executing a SELECT COUNT(*) query if the collection hasn't been
       # loaded and calling collection.size if it has. If it's more likely than not that the collection does
       # have a size larger than zero, and you need to fetch that collection afterwards, it'll take one fewer
@@ -42,27 +49,40 @@ module ActiveRecord
           end
         end
 
-        through_record(record).save!
+        save_through_record(record)
         update_counter(1)
         record
       end
 
-      private
+      # ActiveRecord::Relation#delete_all needs to support joins before we can use a
+      # SQL-only implementation.
+      alias delete_all_on_destroy delete_all
 
-        def through_record(record)
-          through_association = owner.association(through_reflection.name)
-          attributes = construct_join_attributes(record)
+      private
 
-          through_record = Array.wrap(through_association.target).find { |candidate|
-            candidate.attributes.slice(*attributes.keys) == attributes
-          }
+        def through_association
+          @through_association ||= owner.association(through_reflection.name)
+        end
 
-          unless through_record
-            through_record = through_association.build(attributes)
+        # We temporarily cache through record that has been build, because if we build a
+        # through record in build_record and then subsequently call insert_record, then we
+        # want to use the exact same object.
+        #
+        # However, after insert_record has been called, we clear the cache entry because
+        # we want it to be possible to have multiple instances of the same record in an
+        # association
+        def build_through_record(record)
+          @through_records[record.object_id] ||= begin
+            through_record = through_association.build(construct_join_attributes(record))
             through_record.send("#{source_reflection.name}=", record)
+            through_record
           end
+        end
 
-          through_record
+        def save_through_record(record)
+          build_through_record(record).save!
+        ensure
+          @through_records.delete(record.object_id)
         end
 
         def build_record(attributes, options = {})
@@ -73,9 +93,9 @@ module ActiveRecord
           inverse = source_reflection.inverse_of
           if inverse
             if inverse.macro == :has_many
-              record.send(inverse.name) << through_record(record)
+              record.send(inverse.name) << build_through_record(record)
             elsif inverse.macro == :has_one
-              record.send("#{inverse.name}=", through_record(record))
+              record.send("#{inverse.name}=", build_through_record(record))
             end
           end
 
@@ -104,8 +124,7 @@ module ActiveRecord
         def delete_records(records, method)
           ensure_not_nested
 
-          through = owner.association(through_reflection.name)
-          scope   = through.scoped.where(construct_join_attributes(*records))
+          scope = through_association.scoped.where(construct_join_attributes(*records))
 
           case method
           when :destroy
@@ -116,7 +135,7 @@ module ActiveRecord
             count = scope.delete_all
           end
 
-          delete_through_records(through, records)
+          delete_through_records(records)
 
           if through_reflection.macro == :has_many && update_through_counter?(method)
             update_counter(-count, through_reflection)
@@ -125,15 +144,25 @@ module ActiveRecord
           update_counter(-count)
         end
 
-        def delete_through_records(through, records)
-          if through_reflection.macro == :has_many
-            records.each do |record|
-              through.target.delete(through_record(record))
-            end
-          else
-            records.each do |record|
-              through.target = nil if through.target == through_record(record)
+        def through_records_for(record)
+          attributes = construct_join_attributes(record)
+          candidates = Array.wrap(through_association.target)
+          candidates.find_all { |c| c.attributes.slice(*attributes.keys) == attributes }
+        end
+
+        def delete_through_records(records)
+          records.each do |record|
+            through_records = through_records_for(record)
+
+            if through_reflection.macro == :has_many
+              through_records.each { |r| through_association.target.delete(r) }
+            else
+              if through_records.include?(through_association.target)
+                through_association.target = nil
+              end
             end
+
+            @through_records.delete(record.object_id)
           end
         end
 
diff --git a/activerecord/lib/active_record/associations/join_dependency.rb b/activerecord/lib/active_record/associations/join_dependency.rb
index 6c878f0f00..827b01c5ac 100644
--- a/activerecord/lib/active_record/associations/join_dependency.rb
+++ b/activerecord/lib/active_record/associations/join_dependency.rb
@@ -184,7 +184,7 @@ module ActiveRecord
 
         macro = join_part.reflection.macro
         if macro == :has_one
-          return if record.association_cache.key?(join_part.reflection.name)
+          return record.association(join_part.reflection.name).target if record.association_cache.key?(join_part.reflection.name)
           association = join_part.instantiate(row) unless row[join_part.aliased_primary_key].nil?
           set_target_and_inverse(join_part, association, record)
         else
diff --git a/activerecord/lib/active_record/associations/preloader/association.rb b/activerecord/lib/active_record/associations/preloader/association.rb
index 779f8164cc..298decb0f1 100644
--- a/activerecord/lib/active_record/associations/preloader/association.rb
+++ b/activerecord/lib/active_record/associations/preloader/association.rb
@@ -100,6 +100,7 @@ module ActiveRecord
 
           scope = scope.select(preload_options[:select] || options[:select] || table[Arel.star])
           scope = scope.includes(preload_options[:include] || options[:include])
+          scope = scope.eager_load(preload_options[:eager_load] || options[:eager_load])
 
           if options[:as]
             scope = scope.where(
diff --git a/activerecord/lib/active_record/associations/preloader/through_association.rb b/activerecord/lib/active_record/associations/preloader/through_association.rb
index ad6374d09a..97898c53ae 100644
--- a/activerecord/lib/active_record/associations/preloader/through_association.rb
+++ b/activerecord/lib/active_record/associations/preloader/through_association.rb
@@ -53,6 +53,7 @@ module ActiveRecord
           else
             if options[:conditions]
               through_options[:include]    = options[:include] || options[:source]
+              through_options[:eager_load] = options[:eager_load] || options[:source]
               through_options[:conditions] = options[:conditions]
             end
 
diff --git a/activerecord/lib/active_record/associations/through_association.rb b/activerecord/lib/active_record/associations/through_association.rb
index b347a94978..f95e5337c2 100644
--- a/activerecord/lib/active_record/associations/through_association.rb
+++ b/activerecord/lib/active_record/associations/through_association.rb
@@ -44,7 +44,7 @@ module ActiveRecord
           join_attributes = {
             source_reflection.foreign_key =>
               records.map { |record|
-                record.send(source_reflection.association_primary_key)
+                record.send(source_reflection.association_primary_key(reflection.klass))
               }
           }
 
diff --git a/activerecord/lib/active_record/attribute_assignment.rb b/activerecord/lib/active_record/attribute_assignment.rb
new file mode 100644
index 0000000000..bf9fe70b31
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_assignment.rb
@@ -0,0 +1,221 @@
+require 'active_support/concern'
+
+module ActiveRecord
+  module AttributeAssignment
+    extend ActiveSupport::Concern
+    include ActiveModel::MassAssignmentSecurity
+
+    module ClassMethods
+      private
+
+      # The primary key and inheritance column can never be set by mass-assignment for security reasons.
+      def attributes_protected_by_default
+        default = [ primary_key, inheritance_column ]
+        default << 'id' unless primary_key.eql? 'id'
+        default
+      end
+    end
+
+    # Allows you to set all the attributes at once by passing in a hash with keys
+    # matching the attribute names (which again matches the column names).
+    #
+    # If any attributes are protected by either +attr_protected+ or
+    # +attr_accessible+ then only settable attributes will be assigned.
+    #
+    #   class User < ActiveRecord::Base
+    #     attr_protected :is_admin
+    #   end
+    #
+    #   user = User.new
+    #   user.attributes = { :username => 'Phusion', :is_admin => true }
+    #   user.username   # => "Phusion"
+    #   user.is_admin?  # => false
+    def attributes=(new_attributes)
+      return unless new_attributes.is_a?(Hash)
+
+      assign_attributes(new_attributes)
+    end
+
+    # Allows you to set all the attributes for a particular mass-assignment
+    # security role by passing in a hash of attributes with keys matching
+    # the attribute names (which again matches the column names) and the role
+    # name using the :as option.
+    #
+    # To bypass mass-assignment security you can use the :without_protection => true
+    # option.
+    #
+    #   class User < ActiveRecord::Base
+    #     attr_accessible :name
+    #     attr_accessible :name, :is_admin, :as => :admin
+    #   end
+    #
+    #   user = User.new
+    #   user.assign_attributes({ :name => 'Josh', :is_admin => true })
+    #   user.name       # => "Josh"
+    #   user.is_admin?  # => false
+    #
+    #   user = User.new
+    #   user.assign_attributes({ :name => 'Josh', :is_admin => true }, :as => :admin)
+    #   user.name       # => "Josh"
+    #   user.is_admin?  # => true
+    #
+    #   user = User.new
+    #   user.assign_attributes({ :name => 'Josh', :is_admin => true }, :without_protection => true)
+    #   user.name       # => "Josh"
+    #   user.is_admin?  # => true
+    def assign_attributes(new_attributes, options = {})
+      return unless new_attributes
+
+      attributes = new_attributes.stringify_keys
+      multi_parameter_attributes = []
+      nested_parameter_attributes = []
+      @mass_assignment_options = options
+
+      unless options[:without_protection]
+        attributes = sanitize_for_mass_assignment(attributes, mass_assignment_role)
+      end
+
+      attributes.each do |k, v|
+        if k.include?("(")
+          multi_parameter_attributes << [ k, v ]
+        elsif respond_to?("#{k}=")
+          if v.is_a?(Hash)
+            nested_parameter_attributes << [ k, v ]
+          else
+            send("#{k}=", v)
+          end
+        else
+          raise(UnknownAttributeError, "unknown attribute: #{k}")
+        end
+      end
+
+      # assign any deferred nested attributes after the base attributes have been set
+      nested_parameter_attributes.each do |k,v|
+        send("#{k}=", v)
+      end
+
+      @mass_assignment_options = nil
+      assign_multiparameter_attributes(multi_parameter_attributes)
+    end
+
+    protected
+
+    def mass_assignment_options
+      @mass_assignment_options ||= {}
+    end
+
+    def mass_assignment_role
+      mass_assignment_options[:as] || :default
+    end
+
+    private
+
+    # Instantiates objects for all attribute classes that needs more than one constructor parameter. This is done
+    # by calling new on the column type or aggregation type (through composed_of) object with these parameters.
+    # So having the pairs written_on(1) = "2004", written_on(2) = "6", written_on(3) = "24", will instantiate
+    # written_on (a date type) with Date.new("2004", "6", "24"). You can also specify a typecast character in the
+    # parentheses to have the parameters typecasted before they're used in the constructor. Use i for Fixnum,
+    # f for Float, s for String, and a for Array. If all the values for a given attribute are empty, the
+    # attribute will be set to nil.
+    def assign_multiparameter_attributes(pairs)
+      execute_callstack_for_multiparameter_attributes(
+        extract_callstack_for_multiparameter_attributes(pairs)
+      )
+    end
+
+    def instantiate_time_object(name, values)
+      if self.class.send(:create_time_zone_conversion_attribute?, name, column_for_attribute(name))
+        Time.zone.local(*values)
+      else
+        Time.time_with_datetime_fallback(self.class.default_timezone, *values)
+      end
+    end
+
+    def execute_callstack_for_multiparameter_attributes(callstack)
+      errors = []
+      callstack.each do |name, values_with_empty_parameters|
+        begin
+          send(name + "=", read_value_from_parameter(name, values_with_empty_parameters))
+        rescue => ex
+          errors << AttributeAssignmentError.new("error on assignment #{values_with_empty_parameters.values.inspect} to #{name}", ex, name)
+        end
+      end
+      unless errors.empty?
+        raise MultiparameterAssignmentErrors.new(errors), "#{errors.size} error(s) on assignment of multiparameter attributes"
+      end
+    end
+
+    def read_value_from_parameter(name, values_hash_from_param)
+      klass = (self.class.reflect_on_aggregation(name.to_sym) || column_for_attribute(name)).klass
+      if values_hash_from_param.values.all?{|v|v.nil?}
+        nil
+      elsif klass == Time
+        read_time_parameter_value(name, values_hash_from_param)
+      elsif klass == Date
+        read_date_parameter_value(name, values_hash_from_param)
+      else
+        read_other_parameter_value(klass, name, values_hash_from_param)
+      end
+    end
+
+    def read_time_parameter_value(name, values_hash_from_param)
+      # If Date bits were not provided, error
+      raise "Missing Parameter" if [1,2,3].any?{|position| !values_hash_from_param.has_key?(position)}
+      max_position = extract_max_param_for_multiparameter_attributes(values_hash_from_param, 6)
+      # If Date bits were provided but blank, then return nil
+      return nil if (1..3).any? {|position| values_hash_from_param[position].blank?}
+
+      set_values = (1..max_position).collect{|position| values_hash_from_param[position] }
+      # If Time bits are not there, then default to 0
+      (3..5).each {|i| set_values[i] = set_values[i].blank? ? 0 : set_values[i]}
+      instantiate_time_object(name, set_values)
+    end
+
+    def read_date_parameter_value(name, values_hash_from_param)
+      return nil if (1..3).any? {|position| values_hash_from_param[position].blank?}
+      set_values = [values_hash_from_param[1], values_hash_from_param[2], values_hash_from_param[3]]
+      begin
+        Date.new(*set_values)
+      rescue ArgumentError # if Date.new raises an exception on an invalid date
+        instantiate_time_object(name, set_values).to_date # we instantiate Time object and convert it back to a date thus using Time's logic in handling invalid dates
+      end
+    end
+
+    def read_other_parameter_value(klass, name, values_hash_from_param)
+      max_position = extract_max_param_for_multiparameter_attributes(values_hash_from_param)
+      values = (1..max_position).collect do |position|
+        raise "Missing Parameter" if !values_hash_from_param.has_key?(position)
+        values_hash_from_param[position]
+      end
+      klass.new(*values)
+    end
+
+    def extract_max_param_for_multiparameter_attributes(values_hash_from_param, upper_cap = 100)
+      [values_hash_from_param.keys.max,upper_cap].min
+    end
+
+    def extract_callstack_for_multiparameter_attributes(pairs)
+      attributes = { }
+
+      pairs.each do |pair|
+        multiparameter_name, value = pair
+        attribute_name = multiparameter_name.split("(").first
+        attributes[attribute_name] = {} unless attributes.include?(attribute_name)
+
+        parameter_value = value.empty? ? nil : type_cast_attribute_value(multiparameter_name, value)
+        attributes[attribute_name][find_parameter_position(multiparameter_name)] ||= parameter_value
+      end
+
+      attributes
+    end
+
+    def type_cast_attribute_value(multiparameter_name, value)
+      multiparameter_name =~ /\([0-9]*([if])\)/ ? value.send("to_" + $1) : value
+    end
+
+    def find_parameter_position(multiparameter_name)
+      multiparameter_name.scan(/\(([0-9]*).*\)/).first.first.to_i
+    end
+
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_methods.rb b/activerecord/lib/active_record/attribute_methods.rb
index d7bfaa5655..c5834e2fef 100644
--- a/activerecord/lib/active_record/attribute_methods.rb
+++ b/activerecord/lib/active_record/attribute_methods.rb
@@ -7,35 +7,53 @@ module ActiveRecord
     extend ActiveSupport::Concern
     include ActiveModel::AttributeMethods
 
+    included do
+      include Read
+      include Write
+      include BeforeTypeCast
+      include Query
+      include PrimaryKey
+      include TimeZoneConversion
+      include Dirty
+      include Serialization
+
+      # Returns the value of the attribute identified by <tt>attr_name</tt> after it has been typecast (for example,
+      # "2004-12-12" in a data column is cast to a date object, like Date.new(2004, 12, 12)).
+      # (Alias for the protected read_attribute method).
+      alias [] read_attribute
+
+      # Updates the attribute identified by <tt>attr_name</tt> with the specified +value+.
+      # (Alias for the protected write_attribute method).
+      alias []= write_attribute
+
+      public :[], :[]=
+    end
+
     module ClassMethods
       # Generates all the attribute related methods for columns in the database
       # accessors, mutators and query methods.
       def define_attribute_methods
         return if attribute_methods_generated?
-
-        if base_class == self
-          super(column_names)
-          @attribute_methods_generated = true
-        else
-          base_class.define_attribute_methods
-        end
+        superclass.define_attribute_methods unless self == base_class
+        super(column_names)
+        @attribute_methods_generated = true
       end
 
       def attribute_methods_generated?
-        if base_class == self
-          @attribute_methods_generated ||= false
-        else
-          base_class.attribute_methods_generated?
-        end
+        @attribute_methods_generated ||= false
       end
 
-      def undefine_attribute_methods(*args)
-        if base_class == self
-          super
-          @attribute_methods_generated = false
-        else
-          base_class.undefine_attribute_methods(*args)
-        end
+      # We will define the methods as instance methods, but will call them as singleton
+      # methods. This allows us to use method_defined? to check if the method exists,
+      # which is fast and won't give any false positives from the ancestors (because
+      # there are no ancestors).
+      def generated_external_attribute_methods
+        @generated_external_attribute_methods ||= Module.new { extend self }
+      end
+
+      def undefine_attribute_methods
+        super if attribute_methods_generated?
+        @attribute_methods_generated = false
       end
 
       def instance_method_already_implemented?(method_name)
@@ -43,19 +61,46 @@ module ActiveRecord
           raise DangerousAttributeError, "#{method_name} is defined by ActiveRecord"
         end
 
-        super
+        if [Base, Model].include?(active_record_super)
+          super
+        else
+          # If B < A and A defines its own attribute method, then we don't want to overwrite that.
+          defined = method_defined_within?(method_name, superclass, superclass.generated_attribute_methods)
+          defined && !ActiveRecord::Base.method_defined?(method_name) || super
+        end
       end
 
       # A method name is 'dangerous' if it is already defined by Active Record, but
       # not by any ancestors. (So 'puts' is not dangerous but 'save' is.)
-      def dangerous_attribute_method?(method_name)
-        active_record = ActiveRecord::Base
-        superclass    = ActiveRecord::Base.superclass
-
-        (active_record.method_defined?(method_name) ||
-         active_record.private_method_defined?(method_name)) &&
-        !superclass.method_defined?(method_name) &&
-        !superclass.private_method_defined?(method_name)
+      def dangerous_attribute_method?(name)
+        method_defined_within?(name, Base)
+      end
+
+      def method_defined_within?(name, klass, sup = klass.superclass)
+        if klass.method_defined?(name) || klass.private_method_defined?(name)
+          if sup.method_defined?(name) || sup.private_method_defined?(name)
+            klass.instance_method(name).owner != sup.instance_method(name).owner
+          else
+            true
+          end
+        else
+          false
+        end
+      end
+
+      def attribute_method?(attribute)
+        super || (table_exists? && column_names.include?(attribute.to_s.sub(/=$/, '')))
+      end
+
+      # Returns an array of column names as strings if it's not
+      # an abstract class and table exists.
+      # Otherwise it returns an empty array.
+      def attribute_names
+        @attribute_names ||= if !abstract_class? && table_exists?
+            column_names
+          else
+            []
+          end
       end
     end
 
@@ -94,9 +139,105 @@ module ActiveRecord
       super
     end
 
+    # Returns true if the given attribute is in the attributes hash
+    def has_attribute?(attr_name)
+      @attributes.has_key?(attr_name.to_s)
+    end
+
+    # Returns an array of names for the attributes available on this object.
+    def attribute_names
+      @attributes.keys
+    end
+
+    # Returns a hash of all the attributes with their names as keys and the values of the attributes as values.
+    def attributes
+      Hash[@attributes.map { |name, _| [name, read_attribute(name)] }]
+    end
+
+    # Returns an <tt>#inspect</tt>-like string for the value of the
+    # attribute +attr_name+. String attributes are truncated upto 50
+    # characters, and Date and Time attributes are returned in the
+    # <tt>:db</tt> format. Other attributes return the value of
+    # <tt>#inspect</tt> without modification.
+    #
+    #   person = Person.create!(:name => "David Heinemeier Hansson " * 3)
+    #
+    #   person.attribute_for_inspect(:name)
+    #   # => '"David Heinemeier Hansson David Heinemeier Hansson D..."'
+    #
+    #   person.attribute_for_inspect(:created_at)
+    #   # => '"2009-01-12 04:48:57"'
+    def attribute_for_inspect(attr_name)
+      value = read_attribute(attr_name)
+
+      if value.is_a?(String) && value.length > 50
+        "#{value[0..50]}...".inspect
+      elsif value.is_a?(Date) || value.is_a?(Time)
+        %("#{value.to_s(:db)}")
+      else
+        value.inspect
+      end
+    end
+
+    # Returns true if the specified +attribute+ has been set by the user or by a database load and is neither
+    # nil nor empty? (the latter only applies to objects that respond to empty?, most notably Strings).
+    def attribute_present?(attribute)
+      value = read_attribute(attribute)
+      !value.nil? || (value.respond_to?(:empty?) && !value.empty?)
+    end
+
+    # Returns the column object for the named attribute.
+    def column_for_attribute(name)
+      self.class.columns_hash[name.to_s]
+    end
+
     protected
-      def attribute_method?(attr_name)
-        attr_name == 'id' || (defined?(@attributes) && @attributes.include?(attr_name))
+
+    def clone_attributes(reader_method = :read_attribute, attributes = {})
+      attribute_names.each do |name|
+        attributes[name] = clone_attribute_value(reader_method, name)
       end
+      attributes
+    end
+
+    def clone_attribute_value(reader_method, attribute_name)
+      value = send(reader_method, attribute_name)
+      value.duplicable? ? value.clone : value
+    rescue TypeError, NoMethodError
+      value
+    end
+
+    # Returns a copy of the attributes hash where all the values have been safely quoted for use in
+    # an Arel insert/update method.
+    def arel_attributes_values(include_primary_key = true, include_readonly_attributes = true, attribute_names = @attributes.keys)
+      attrs      = {}
+      klass      = self.class
+      arel_table = klass.arel_table
+
+      attribute_names.each do |name|
+        if (column = column_for_attribute(name)) && (include_primary_key || !column.primary)
+
+          if include_readonly_attributes || !self.class.readonly_attributes.include?(name)
+
+            value = if klass.serialized_attributes.include?(name)
+                      @attributes[name].serialized_value
+                    else
+                      # FIXME: we need @attributes to be used consistently.
+                      # If the values stored in @attributes were already type
+                      # casted, this code could be simplified
+                      read_attribute(name)
+                    end
+
+            attrs[arel_table[name]] = value
+          end
+        end
+      end
+
+      attrs
+    end
+
+    def attribute_method?(attr_name)
+      attr_name == 'id' || (defined?(@attributes) && @attributes.include?(attr_name))
+    end
   end
 end
diff --git a/activerecord/lib/active_record/attribute_methods/dirty.rb b/activerecord/lib/active_record/attribute_methods/dirty.rb
index 3eff3d54e3..40e4a97e73 100644
--- a/activerecord/lib/active_record/attribute_methods/dirty.rb
+++ b/activerecord/lib/active_record/attribute_methods/dirty.rb
@@ -13,7 +13,7 @@ module ActiveRecord
           raise "You cannot include Dirty after Timestamp"
         end
 
-        class_attribute :partial_updates
+        config_attribute :partial_updates
         self.partial_updates = true
       end
 
@@ -34,9 +34,9 @@ module ActiveRecord
           @previously_changed = changes
           @changed_attributes.clear
         end
-        rescue
-          IdentityMap.remove(self) if IdentityMap.enabled?
-          raise
+      rescue
+        IdentityMap.remove(self) if IdentityMap.enabled?
+        raise
       end
 
       # <tt>reload</tt> the record and clears changed attributes.
diff --git a/activerecord/lib/active_record/attribute_methods/primary_key.rb b/activerecord/lib/active_record/attribute_methods/primary_key.rb
index 36d7f4ad11..a7785f8786 100644
--- a/activerecord/lib/active_record/attribute_methods/primary_key.rb
+++ b/activerecord/lib/active_record/attribute_methods/primary_key.rb
@@ -5,16 +5,48 @@ module ActiveRecord
 
       # Returns this record's primary key value wrapped in an Array if one is available
       def to_key
-        key = send(self.class.primary_key)
+        key = self.id
         [key] if key
       end
 
+      # Returns the primary key value
+      def id
+        read_attribute(self.class.primary_key)
+      end
+
+      # Sets the primary key value
+      def id=(value)
+        write_attribute(self.class.primary_key, value)
+      end
+
+      # Queries the primary key value
+      def id?
+        query_attribute(self.class.primary_key)
+      end
+
       module ClassMethods
+        def define_method_attribute(attr_name)
+          super
+
+          if attr_name == primary_key && attr_name != 'id'
+            generated_attribute_methods.send(:alias_method, :id, primary_key)
+            generated_external_attribute_methods.module_eval <<-CODE, __FILE__, __LINE__
+              def id(v, attributes, attributes_cache, attr_name)
+                attr_name = '#{primary_key}'
+                send(attr_name, attributes[attr_name], attributes, attributes_cache, attr_name)
+              end
+            CODE
+          end
+        end
+
+        def dangerous_attribute_method?(method_name)
+          super && !['id', 'id=', 'id?'].include?(method_name)
+        end
+
         # Defines the primary key field -- can be overridden in subclasses. Overwriting will negate any effect of the
         # primary_key_prefix_type setting, though.
         def primary_key
-          @primary_key ||= reset_primary_key
-          raise ActiveRecord::UnknownPrimaryKey.new(self) unless @primary_key
+          @primary_key = reset_primary_key unless defined? @primary_key
           @primary_key
         end
 
@@ -24,16 +56,11 @@ module ActiveRecord
         end
 
         def reset_primary_key #:nodoc:
-          key = self == base_class ? get_primary_key(base_class.name) :
-            base_class.primary_key
-
-          set_primary_key(key)
-          key
-        end
-
-        def primary_key? #:nodoc:
-          @primary_key ||= reset_primary_key
-          !@primary_key.nil?
+          if self == base_class
+            self.primary_key = get_primary_key(base_class.name)
+          else
+            self.primary_key = base_class.primary_key
+          end
         end
 
         def get_primary_key(base_name) #:nodoc:
@@ -45,35 +72,32 @@ module ActiveRecord
           when :table_name_with_underscore
             base_name.foreign_key
           else
-            if ActiveRecord::Base != self && connection.table_exists?(table_name)
-              connection.primary_key(table_name)
+            if ActiveRecord::Base != self && table_exists?
+              connection.schema_cache.primary_keys[table_name]
             else
               'id'
             end
           end
         end
 
-        attr_accessor :original_primary_key
-
-        # Attribute writer for the primary key column
-        def primary_key=(value)
-          @quoted_primary_key = nil
-          @primary_key = value
-        end
-
-        # Sets the name of the primary key column to use to the given value,
-        # or (if the value is nil or false) to the value returned by the given
-        # block.
+        # Sets the name of the primary key column.
+        #
+        #   class Project < ActiveRecord::Base
+        #     self.primary_key = "sysid"
+        #   end
+        #
+        # You can also define the primary_key method yourself:
         #
         #   class Project < ActiveRecord::Base
-        #     set_primary_key "sysid"
+        #     def self.primary_key
+        #       "foo_" + super
+        #     end
         #   end
-        def set_primary_key(value = nil, &block)
-          @quoted_primary_key = nil
-          @primary_key ||= ''
-          self.original_primary_key = @primary_key
-          value &&= value.to_s
-          self.primary_key = block_given? ? instance_eval(&block) : value
+        #   Project.primary_key # => "foo_id"
+        def primary_key=(value)
+          @original_primary_key = @primary_key if defined?(@primary_key)
+          @primary_key          = value && value.to_s
+          @quoted_primary_key   = nil
         end
       end
     end
diff --git a/activerecord/lib/active_record/attribute_methods/read.rb b/activerecord/lib/active_record/attribute_methods/read.rb
index 8566ecad14..964c4123ef 100644
--- a/activerecord/lib/active_record/attribute_methods/read.rb
+++ b/activerecord/lib/active_record/attribute_methods/read.rb
@@ -6,11 +6,8 @@ module ActiveRecord
       ATTRIBUTE_TYPES_CACHED_BY_DEFAULT = [:datetime, :timestamp, :time, :date]
 
       included do
-        cattr_accessor :attribute_types_cached_by_default, :instance_writer => false
+        config_attribute :attribute_types_cached_by_default, :global => true
         self.attribute_types_cached_by_default = ATTRIBUTE_TYPES_CACHED_BY_DEFAULT
-
-        # Undefine id so it can be used as an attribute name
-        undef_method(:id) if method_defined?(:id)
       end
 
       module ClassMethods
@@ -32,107 +29,101 @@ module ActiveRecord
           cached_attributes.include?(attr_name)
         end
 
+        def undefine_attribute_methods
+          generated_external_attribute_methods.module_eval do
+            instance_methods.each { |m| undef_method(m) }
+          end
+
+          super
+        end
+
+        def type_cast_attribute(attr_name, attributes, cache = {}) #:nodoc:
+          return unless attr_name
+          attr_name = attr_name.to_s
+
+          if generated_external_attribute_methods.method_defined?(attr_name)
+            if attributes.has_key?(attr_name) || attr_name == 'id'
+              generated_external_attribute_methods.send(attr_name, attributes[attr_name], attributes, cache, attr_name)
+            end
+          elsif !attribute_methods_generated?
+            # If we haven't generated the caster methods yet, do that and
+            # then try again
+            define_attribute_methods
+            type_cast_attribute(attr_name, attributes, cache)
+          else
+            # If we get here, the attribute has no associated DB column, so
+            # just return it verbatim.
+            attributes[attr_name]
+          end
+        end
+
         protected
+          # We want to generate the methods via module_eval rather than define_method,
+          # because define_method is slower on dispatch and uses more memory (because it
+          # creates a closure).
+          #
+          # But sometimes the database might return columns with characters that are not
+          # allowed in normal method names (like 'my_column(omg)'. So to work around this
+          # we first define with the __temp__ identifier, and then use alias method to
+          # rename it to what we want.
           def define_method_attribute(attr_name)
-            if serialized_attributes.include?(attr_name)
-              define_read_method_for_serialized_attribute(attr_name)
-            else
-              define_read_method(attr_name, attr_name, columns_hash[attr_name])
-            end
+            cast_code = attribute_cast_code(attr_name)
 
-            if primary_key? && attr_name == primary_key && attr_name != "id"
-              define_read_method('id', attr_name, columns_hash[attr_name])
-            end
+            generated_attribute_methods.module_eval <<-STR, __FILE__, __LINE__ + 1
+              def __temp__
+                #{internal_attribute_access_code(attr_name, cast_code)}
+              end
+              alias_method '#{attr_name}', :__temp__
+              undef_method :__temp__
+            STR
+
+            generated_external_attribute_methods.module_eval <<-STR, __FILE__, __LINE__ + 1
+              def __temp__(v, attributes, attributes_cache, attr_name)
+                #{external_attribute_access_code(attr_name, cast_code)}
+              end
+              alias_method '#{attr_name}', :__temp__
+              undef_method :__temp__
+            STR
           end
 
         private
           def cacheable_column?(column)
-            serialized_attributes.include?(column.name) || attribute_types_cached_by_default.include?(column.type)
-          end
-
-          # Define read method for serialized attribute.
-          def define_read_method_for_serialized_attribute(attr_name)
-            access_code = "@attributes_cache['#{attr_name}'] ||= @attributes['#{attr_name}']"
-            generated_attribute_methods.module_eval("def _#{attr_name}; #{access_code}; end; alias #{attr_name} _#{attr_name}", __FILE__, __LINE__)
+            attribute_types_cached_by_default.include?(column.type)
           end
 
-          # Define an attribute reader method. Cope with nil column.
-          # method_name is the same as attr_name except when a non-standard primary key is used,
-          # we still define #id as an accessor for the key
-          def define_read_method(method_name, attr_name, column)
-            cast_code = column.type_cast_code('v')
-            access_code = "(v=@attributes['#{attr_name}']) && #{cast_code}"
+          def internal_attribute_access_code(attr_name, cast_code)
+            access_code = "(v=@attributes[attr_name]) && #{cast_code}"
 
-            unless primary_key? && attr_name.to_s == primary_key.to_s
-              access_code.insert(0, "missing_attribute('#{attr_name}', caller) unless @attributes.has_key?('#{attr_name}'); ")
+            unless attr_name == primary_key
+              access_code.insert(0, "missing_attribute(attr_name, caller) unless @attributes.has_key?(attr_name); ")
             end
 
             if cache_attribute?(attr_name)
-              access_code = "@attributes_cache['#{attr_name}'] ||= (#{access_code})"
+              access_code = "@attributes_cache[attr_name] ||= (#{access_code})"
             end
 
-            # Where possible, generate the method by evalling a string, as this will result in
-            # faster accesses because it avoids the block eval and then string eval incurred
-            # by the second branch.
-            #
-            # The second, slower, branch is necessary to support instances where the database
-            # returns columns with extra stuff in (like 'my_column(omg)').
-            if method_name =~ ActiveModel::AttributeMethods::COMPILABLE_REGEXP
-              generated_attribute_methods.module_eval <<-STR, __FILE__, __LINE__
-                def _#{method_name}
-                  #{access_code}
-                end
-
-                alias #{method_name} _#{method_name}
-              STR
-            else
-              generated_attribute_methods.module_eval do
-                define_method("_#{method_name}") { eval(access_code) }
-                alias_method(method_name, "_#{method_name}")
-              end
-            end
+            "attr_name = '#{attr_name}'; #{access_code}"
           end
-      end
 
-      # Returns the value of the attribute identified by <tt>attr_name</tt> after it has been typecast (for example,
-      # "2004-12-12" in a data column is cast to a date object, like Date.new(2004, 12, 12)).
-      def read_attribute(attr_name)
-        method = "_#{attr_name}"
-        if respond_to? method
-          send method if @attributes.has_key?(attr_name.to_s)
-        else
-          _read_attribute attr_name
-        end
-      end
+          def external_attribute_access_code(attr_name, cast_code)
+            access_code = "v && #{cast_code}"
 
-      def _read_attribute(attr_name)
-        attr_name = attr_name.to_s
-        attr_name = self.class.primary_key? && self.class.primary_key if attr_name == 'id'
-        value = @attributes[attr_name]
-        unless value.nil?
-          if column = column_for_attribute(attr_name)
-            if unserializable_attribute?(attr_name, column)
-              unserialize_attribute(attr_name)
-            else
-              column.type_cast(value)
+            if cache_attribute?(attr_name)
+              access_code = "attributes_cache[attr_name] ||= (#{access_code})"
             end
-          else
-            value
+
+            access_code
           end
-        end
-      end
 
-      # Returns true if the attribute is of a text column and marked for serialization.
-      def unserializable_attribute?(attr_name, column)
-        column.text? && self.class.serialized_attributes.include?(attr_name)
+          def attribute_cast_code(attr_name)
+            columns_hash[attr_name].type_cast_code('v')
+          end
       end
 
-      # Returns the unserialized object of the attribute.
-      def unserialize_attribute(attr_name)
-        coder = self.class.serialized_attributes[attr_name]
-        unserialized_object = coder.load(@attributes[attr_name])
-
-        @attributes.frozen? ? unserialized_object : @attributes[attr_name] = unserialized_object
+      # Returns the value of the attribute identified by <tt>attr_name</tt> after it has been typecast (for example,
+      # "2004-12-12" in a data column is cast to a date object, like Date.new(2004, 12, 12)).
+      def read_attribute(attr_name)
+        self.class.type_cast_attribute(attr_name, @attributes, @attributes_cache)
       end
 
       private
diff --git a/activerecord/lib/active_record/attribute_methods/serialization.rb b/activerecord/lib/active_record/attribute_methods/serialization.rb
new file mode 100644
index 0000000000..0c8e4e4b9a
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods/serialization.rb
@@ -0,0 +1,93 @@
+module ActiveRecord
+  module AttributeMethods
+    module Serialization
+      extend ActiveSupport::Concern
+
+      included do
+        # Returns a hash of all the attributes that have been specified for serialization as
+        # keys and their class restriction as values.
+        config_attribute :serialized_attributes
+        self.serialized_attributes = {}
+      end
+
+      class Attribute < Struct.new(:coder, :value, :state)
+        def unserialized_value
+          state == :serialized ? unserialize : value
+        end
+
+        def serialized_value
+          state == :unserialized ? serialize : value
+        end
+
+        def unserialize
+          self.state = :unserialized
+          self.value = coder.load(value)
+        end
+
+        def serialize
+          self.state = :serialized
+          self.value = coder.dump(value)
+        end
+      end
+
+      module ClassMethods
+        # If you have an attribute that needs to be saved to the database as an object, and retrieved as the same object,
+        # then specify the name of that attribute using this method and it will be handled automatically.
+        # The serialization is done through YAML. If +class_name+ is specified, the serialized object must be of that
+        # class on retrieval or SerializationTypeMismatch will be raised.
+        #
+        # ==== Parameters
+        #
+        # * +attr_name+ - The field name that should be serialized.
+        # * +class_name+ - Optional, class name that the object type should be equal to.
+        #
+        # ==== Example
+        #   # Serialize a preferences attribute
+        #   class User < ActiveRecord::Base
+        #     serialize :preferences
+        #   end
+        def serialize(attr_name, class_name = Object)
+          coder = if [:load, :dump].all? { |x| class_name.respond_to?(x) }
+                    class_name
+                  else
+                    Coders::YAMLColumn.new(class_name)
+                  end
+
+          # merge new serialized attribute and create new hash to ensure that each class in inheritance hierarchy
+          # has its own hash of own serialized attributes
+          self.serialized_attributes = serialized_attributes.merge(attr_name.to_s => coder)
+        end
+
+        def initialize_attributes(attributes) #:nodoc:
+          super
+
+          serialized_attributes.each do |key, coder|
+            if attributes.key?(key)
+              attributes[key] = Attribute.new(coder, attributes[key], :serialized)
+            end
+          end
+
+          attributes
+        end
+
+        private
+
+        def attribute_cast_code(attr_name)
+          if serialized_attributes.include?(attr_name)
+            "v.unserialized_value"
+          else
+            super
+          end
+        end
+      end
+
+      def type_cast_attribute_for_write(column, value)
+        if column && coder = self.class.serialized_attributes[column.name]
+          Attribute.new(coder, value, :unserialized)
+        else
+          super
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb b/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
index 62a3cfa9a5..2f86e32f41 100644
--- a/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
+++ b/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
@@ -7,30 +7,25 @@ module ActiveRecord
       extend ActiveSupport::Concern
 
       included do
-        cattr_accessor :time_zone_aware_attributes, :instance_writer => false
+        config_attribute :time_zone_aware_attributes, :global => true
         self.time_zone_aware_attributes = false
 
-        class_attribute :skip_time_zone_conversion_for_attributes, :instance_writer => false
+        config_attribute :skip_time_zone_conversion_for_attributes
         self.skip_time_zone_conversion_for_attributes = []
       end
 
       module ClassMethods
         protected
-          # Defined for all +datetime+ and +timestamp+ attributes when +time_zone_aware_attributes+ are enabled.
-          # This enhanced read method automatically converts the UTC time stored in the database to the time
+          # The enhanced read method automatically converts the UTC time stored in the database to the time
           # zone stored in Time.zone.
-          def define_method_attribute(attr_name)
-            if create_time_zone_conversion_attribute?(attr_name, columns_hash[attr_name])
-              method_body, line = <<-EOV, __LINE__ + 1
-                def _#{attr_name}
-                  cached = @attributes_cache['#{attr_name}']
-                  return cached if cached
-                  time = _read_attribute('#{attr_name}')
-                  @attributes_cache['#{attr_name}'] = time.acts_like?(:time) ? time.in_time_zone : time
-                end
-                alias #{attr_name} _#{attr_name}
-              EOV
-              generated_attribute_methods.module_eval(method_body, __FILE__, line)
+          def attribute_cast_code(attr_name)
+            column = columns_hash[attr_name]
+
+            if create_time_zone_conversion_attribute?(attr_name, column)
+              typecast             = "v = #{super}"
+              time_zone_conversion = "v.acts_like?(:time) ? v.in_time_zone : v"
+
+              "((#{typecast}) && (#{time_zone_conversion}))"
             else
               super
             end
diff --git a/activerecord/lib/active_record/attribute_methods/write.rb b/activerecord/lib/active_record/attribute_methods/write.rb
index 4db6d71ba6..fde55b95da 100644
--- a/activerecord/lib/active_record/attribute_methods/write.rb
+++ b/activerecord/lib/active_record/attribute_methods/write.rb
@@ -10,17 +10,13 @@ module ActiveRecord
       module ClassMethods
         protected
           def define_method_attribute=(attr_name)
-            if attr_name =~ ActiveModel::AttributeMethods::COMPILABLE_REGEXP
+            if attr_name =~ ActiveModel::AttributeMethods::NAME_COMPILABLE_REGEXP
               generated_attribute_methods.module_eval("def #{attr_name}=(new_value); write_attribute('#{attr_name}', new_value); end", __FILE__, __LINE__)
             else
               generated_attribute_methods.send(:define_method, "#{attr_name}=") do |new_value|
                 write_attribute(attr_name, new_value)
               end
             end
-
-            if primary_key? && attr_name == primary_key && attr_name != "id"
-              generated_attribute_methods.module_eval("alias :id= :'#{primary_key}='")
-            end
           end
       end
 
@@ -32,10 +28,8 @@ module ActiveRecord
         @attributes_cache.delete(attr_name)
         column = column_for_attribute(attr_name)
 
-        if column && column.number?
-          @attributes[attr_name] = convert_number_column_value(value)
-        elsif column || @attributes.has_key?(attr_name)
-          @attributes[attr_name] = value
+        if column || @attributes.has_key?(attr_name)
+          @attributes[attr_name] = type_cast_attribute_for_write(column, value)
         else
           raise ActiveModel::MissingAttributeError, "can't write unknown attribute `#{attr_name}'"
         end
@@ -47,6 +41,26 @@ module ActiveRecord
         def attribute=(attribute_name, value)
           write_attribute(attribute_name, value)
         end
+
+        def type_cast_attribute_for_write(column, value)
+          if column && column.number?
+            convert_number_column_value(value)
+          else
+            value
+          end
+        end
+
+        def convert_number_column_value(value)
+          if value == false
+            0
+          elsif value == true
+            1
+          elsif value.is_a?(String) && value.blank?
+            nil
+          else
+            value
+          end
+        end
     end
   end
 end
diff --git a/activerecord/lib/active_record/autosave_association.rb b/activerecord/lib/active_record/autosave_association.rb
index 056170d82a..c86eaba498 100644
--- a/activerecord/lib/active_record/autosave_association.rb
+++ b/activerecord/lib/active_record/autosave_association.rb
@@ -21,6 +21,21 @@ module ActiveRecord
   # Note that <tt>:autosave => false</tt> is not same as not declaring <tt>:autosave</tt>.
   # When the <tt>:autosave</tt> option is not present new associations are saved.
   #
+  # == Validation
+  #
+  # Children records are validated unless <tt>:validate</tt> is +false+.
+  #
+  # == Callbacks
+  #
+  # Association with autosave option defines several callbacks on your
+  # model (before_save, after_create, after_update). Please note that
+  # callbacks are executed in the order they were defined in
+  # model. You should avoid modyfing the association content, before
+  # autosave callbacks are executed. Placing your callbacks after
+  # associations is usually a good practice.
+  #
+  # == Examples
+  #
   # === One-to-one Example
   #
   #   class Post
@@ -109,10 +124,7 @@ module ActiveRecord
   # Now it _is_ removed from the database:
   #
   #   Comment.find_by_id(id).nil? # => true
-  #
-  # === Validation
-  #
-  # Children records are validated unless <tt>:validate</tt> is +false+.
+
   module AutosaveAssociation
     extend ActiveSupport::Concern
 
@@ -264,7 +276,7 @@ module ActiveRecord
     # turned on for the association.
     def validate_single_association(reflection)
       association = association_instance_get(reflection.name)
-      record      = association && association.target
+      record      = association && association.reader
       association_valid?(reflection, record) if record
     end
 
@@ -331,7 +343,7 @@ module ActiveRecord
               if autosave
                 saved = association.insert_record(record, false)
               else
-                association.insert_record(record)
+                association.insert_record(record) unless reflection.nested?
               end
             elsif autosave
               saved = record.save(:validate => false)
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
index 137b4c6534..d29cf82dad 100644
--- a/activerecord/lib/active_record/base.rb
+++ b/activerecord/lib/active_record/base.rb
@@ -23,9 +23,11 @@ require 'active_support/core_ext/module/delegation'
 require 'active_support/core_ext/module/introspection'
 require 'active_support/core_ext/object/duplicable'
 require 'active_support/core_ext/object/blank'
+require 'active_support/deprecation'
 require 'arel'
 require 'active_record/errors'
 require 'active_record/log_subscriber'
+require 'active_record/explain_subscriber'
 
 module ActiveRecord #:nodoc:
   # = Active Record
@@ -115,8 +117,8 @@ module ActiveRecord #:nodoc:
   # When joining tables, nested hashes or keys written in the form 'table_name.column_name'
   # can be used to qualify the table name of a particular condition. For instance:
   #
-  #   Student.joins(:schools).where(:schools => { :type => 'public' })
-  #   Student.joins(:schools).where('schools.type' => 'public' )
+  #   Student.joins(:schools).where(:schools => { :category => 'public' })
+  #   Student.joins(:schools).where('schools.category' => 'public' )
   #
   # == Overwriting default accessors
   #
@@ -325,1843 +327,8 @@ module ActiveRecord #:nodoc:
   # So it's possible to assign a logger to the class through <tt>Base.logger=</tt> which will then be used by all
   # instances in the current object space.
   class Base
-    ##
-    # :singleton-method:
-    # Accepts a logger conforming to the interface of Log4r or the default Ruby 1.8+ Logger class,
-    # which is then passed on to any new database connections made and which can be retrieved on both
-    # a class and instance level by calling +logger+.
-    cattr_accessor :logger, :instance_writer => false
-
-    ##
-    # :singleton-method:
-    # Contains the database configuration - as is typically stored in config/database.yml -
-    # as a Hash.
-    #
-    # For example, the following database.yml...
-    #
-    #   development:
-    #     adapter: sqlite3
-    #     database: db/development.sqlite3
-    #
-    #   production:
-    #     adapter: sqlite3
-    #     database: db/production.sqlite3
-    #
-    # ...would result in ActiveRecord::Base.configurations to look like this:
-    #
-    #   {
-    #      'development' => {
-    #         'adapter'  => 'sqlite3',
-    #         'database' => 'db/development.sqlite3'
-    #      },
-    #      'production' => {
-    #         'adapter'  => 'sqlite3',
-    #         'database' => 'db/production.sqlite3'
-    #      }
-    #   }
-    cattr_accessor :configurations, :instance_writer => false
-    @@configurations = {}
-
-    ##
-    # :singleton-method:
-    # Accessor for the prefix type that will be prepended to every primary key column name.
-    # The options are :table_name and :table_name_with_underscore. If the first is specified,
-    # the Product class will look for "productid" instead of "id" as the primary column. If the
-    # latter is specified, the Product class will look for "product_id" instead of "id". Remember
-    # that this is a global setting for all Active Records.
-    cattr_accessor :primary_key_prefix_type, :instance_writer => false
-    @@primary_key_prefix_type = nil
-
-    ##
-    # :singleton-method:
-    # Accessor for the name of the prefix string to prepend to every table name. So if set
-    # to "basecamp_", all table names will be named like "basecamp_projects", "basecamp_people",
-    # etc. This is a convenient way of creating a namespace for tables in a shared database.
-    # By default, the prefix is the empty string.
-    #
-    # If you are organising your models within modules you can add a prefix to the models within
-    # a namespace by defining a singleton method in the parent module called table_name_prefix which
-    # returns your chosen prefix.
-    class_attribute :table_name_prefix, :instance_writer => false
-    self.table_name_prefix = ""
-
-    ##
-    # :singleton-method:
-    # Works like +table_name_prefix+, but appends instead of prepends (set to "_basecamp" gives "projects_basecamp",
-    # "people_basecamp"). By default, the suffix is the empty string.
-    class_attribute :table_name_suffix, :instance_writer => false
-    self.table_name_suffix = ""
-
-    ##
-    # :singleton-method:
-    # Indicates whether table names should be the pluralized versions of the corresponding class names.
-    # If true, the default table name for a Product class will be +products+. If false, it would just be +product+.
-    # See table_name for the full rules on table/class naming. This is true, by default.
-    class_attribute :pluralize_table_names, :instance_writer => false
-    self.pluralize_table_names = true
-
-    ##
-    # :singleton-method:
-    # Determines whether to use Time.local (using :local) or Time.utc (using :utc) when pulling
-    # dates and times from the database. This is set to :local by default.
-    cattr_accessor :default_timezone, :instance_writer => false
-    @@default_timezone = :local
-
-    ##
-    # :singleton-method:
-    # Specifies the format to use when dumping the database schema with Rails'
-    # Rakefile. If :sql, the schema is dumped as (potentially database-
-    # specific) SQL statements. If :ruby, the schema is dumped as an
-    # ActiveRecord::Schema file which can be loaded into any database that
-    # supports migrations. Use :ruby if you want to have different database
-    # adapters for, e.g., your development and test environments.
-    cattr_accessor :schema_format , :instance_writer => false
-    @@schema_format = :ruby
-
-    ##
-    # :singleton-method:
-    # Specify whether or not to use timestamps for migration versions
-    cattr_accessor :timestamped_migrations , :instance_writer => false
-    @@timestamped_migrations = true
-
-    # Determine whether to store the full constant name including namespace when using STI
-    class_attribute :store_full_sti_class
-    self.store_full_sti_class = true
-
-    # Stores the default scope for the class
-    class_attribute :default_scopes, :instance_writer => false
-    self.default_scopes = []
-
-    # Returns a hash of all the attributes that have been specified for serialization as
-    # keys and their class restriction as values.
-    class_attribute :serialized_attributes
-    self.serialized_attributes = {}
-
-    class_attribute :_attr_readonly, :instance_writer => false
-    self._attr_readonly = []
-
-    class << self # Class methods
-      delegate :find, :first, :first!, :last, :last!, :all, :exists?, :any?, :many?, :to => :scoped
-      delegate :first_or_create, :first_or_create!, :first_or_initialize, :to => :scoped
-      delegate :destroy, :destroy_all, :delete, :delete_all, :update, :update_all, :to => :scoped
-      delegate :find_each, :find_in_batches, :to => :scoped
-      delegate :select, :group, :order, :except, :reorder, :limit, :offset, :joins, :where, :preload, :eager_load, :includes, :from, :lock, :readonly, :having, :create_with, :to => :scoped
-      delegate :count, :average, :minimum, :maximum, :sum, :calculate, :to => :scoped
-
-      # Executes a custom SQL query against your database and returns all the results. The results will
-      # be returned as an array with columns requested encapsulated as attributes of the model you call
-      # this method from. If you call <tt>Product.find_by_sql</tt> then the results will be returned in
-      # a Product object with the attributes you specified in the SQL query.
-      #
-      # If you call a complicated SQL query which spans multiple tables the columns specified by the
-      # SELECT will be attributes of the model, whether or not they are columns of the corresponding
-      # table.
-      #
-      # The +sql+ parameter is a full SQL query as a string. It will be called as is, there will be
-      # no database agnostic conversions performed. This should be a last resort because using, for example,
-      # MySQL specific terms will lock you to using that particular database engine or require you to
-      # change your call if you switch engines.
-      #
-      # ==== Examples
-      #   # A simple SQL query spanning multiple tables
-      #   Post.find_by_sql "SELECT p.title, c.author FROM posts p, comments c WHERE p.id = c.post_id"
-      #   > [#<Post:0x36bff9c @attributes={"title"=>"Ruby Meetup", "first_name"=>"Quentin"}>, ...]
-      #
-      #   # You can use the same string replacement techniques as you can with ActiveRecord#find
-      #   Post.find_by_sql ["SELECT title FROM posts WHERE author = ? AND created > ?", author_id, start_date]
-      #   > [#<Post:0x36bff9c @attributes={"title"=>"The Cheap Man Buys Twice"}>, ...]
-      def find_by_sql(sql, binds = [])
-        connection.select_all(sanitize_sql(sql), "#{name} Load", binds).collect! { |record| instantiate(record) }
-      end
-
-      # Creates an object (or multiple objects) and saves it to the database, if validations pass.
-      # The resulting object is returned whether the object was saved successfully to the database or not.
-      #
-      # The +attributes+ parameter can be either be a Hash or an Array of Hashes. These Hashes describe the
-      # attributes on the objects that are to be created.
-      #
-      # +create+ respects mass-assignment security and accepts either +:as+ or +:without_protection+ options
-      # in the +options+ parameter.
-      #
-      # ==== Examples
-      #   # Create a single new object
-      #   User.create(:first_name => 'Jamie')
-      #
-      #   # Create a single new object using the :admin mass-assignment security role
-      #   User.create({ :first_name => 'Jamie', :is_admin => true }, :as => :admin)
-      #
-      #   # Create a single new object bypassing mass-assignment security
-      #   User.create({ :first_name => 'Jamie', :is_admin => true }, :without_protection => true)
-      #
-      #   # Create an Array of new objects
-      #   User.create([{ :first_name => 'Jamie' }, { :first_name => 'Jeremy' }])
-      #
-      #   # Create a single object and pass it into a block to set other attributes.
-      #   User.create(:first_name => 'Jamie') do |u|
-      #     u.is_admin = false
-      #   end
-      #
-      #   # Creating an Array of new objects using a block, where the block is executed for each object:
-      #   User.create([{ :first_name => 'Jamie' }, { :first_name => 'Jeremy' }]) do |u|
-      #     u.is_admin = false
-      #   end
-      def create(attributes = nil, options = {}, &block)
-        if attributes.is_a?(Array)
-          attributes.collect { |attr| create(attr, options, &block) }
-        else
-          object = new(attributes, options, &block)
-          object.save
-          object
-        end
-      end
-
-      # Returns the result of an SQL statement that should only include a COUNT(*) in the SELECT part.
-      # The use of this method should be restricted to complicated SQL queries that can't be executed
-      # using the ActiveRecord::Calculations class methods. Look into those before using this.
-      #
-      # ==== Parameters
-      #
-      # * +sql+ - An SQL statement which should return a count query from the database, see the example below.
-      #
-      # ==== Examples
-      #
-      #   Product.count_by_sql "SELECT COUNT(*) FROM sales s, customers c WHERE s.customer_id = c.id"
-      def count_by_sql(sql)
-        sql = sanitize_conditions(sql)
-        connection.select_value(sql, "#{name} Count").to_i
-      end
-
-      # Attributes listed as readonly will be used to create a new record but update operations will
-      # ignore these fields.
-      def attr_readonly(*attributes)
-        self._attr_readonly = Set.new(attributes.map { |a| a.to_s }) + (self._attr_readonly || [])
-      end
-
-      # Returns an array of all the attributes that have been specified as readonly.
-      def readonly_attributes
-        self._attr_readonly
-      end
-
-      # If you have an attribute that needs to be saved to the database as an object, and retrieved as the same object,
-      # then specify the name of that attribute using this method and it will be handled automatically.
-      # The serialization is done through YAML. If +class_name+ is specified, the serialized object must be of that
-      # class on retrieval or SerializationTypeMismatch will be raised.
-      #
-      # ==== Parameters
-      #
-      # * +attr_name+ - The field name that should be serialized.
-      # * +class_name+ - Optional, class name that the object type should be equal to.
-      #
-      # ==== Example
-      #   # Serialize a preferences attribute
-      #   class User < ActiveRecord::Base
-      #     serialize :preferences
-      #   end
-      def serialize(attr_name, class_name = Object)
-        coder = if [:load, :dump].all? { |x| class_name.respond_to?(x) }
-                  class_name
-                else
-                  Coders::YAMLColumn.new(class_name)
-                end
-
-        # merge new serialized attribute and create new hash to ensure that each class in inheritance hierarchy
-        # has its own hash of own serialized attributes
-        self.serialized_attributes = serialized_attributes.merge(attr_name.to_s => coder)
-      end
-
-      # Guesses the table name (in forced lower-case) based on the name of the class in the
-      # inheritance hierarchy descending directly from ActiveRecord::Base. So if the hierarchy
-      # looks like: Reply < Message < ActiveRecord::Base, then Message is used
-      # to guess the table name even when called on Reply. The rules used to do the guess
-      # are handled by the Inflector class in Active Support, which knows almost all common
-      # English inflections. You can add new inflections in config/initializers/inflections.rb.
-      #
-      # Nested classes are given table names prefixed by the singular form of
-      # the parent's table name. Enclosing modules are not considered.
-      #
-      # ==== Examples
-      #
-      #   class Invoice < ActiveRecord::Base
-      #   end
-      #
-      #   file                  class               table_name
-      #   invoice.rb            Invoice             invoices
-      #
-      #   class Invoice < ActiveRecord::Base
-      #     class Lineitem < ActiveRecord::Base
-      #     end
-      #   end
-      #
-      #   file                  class               table_name
-      #   invoice.rb            Invoice::Lineitem   invoice_lineitems
-      #
-      #   module Invoice
-      #     class Lineitem < ActiveRecord::Base
-      #     end
-      #   end
-      #
-      #   file                  class               table_name
-      #   invoice/lineitem.rb   Invoice::Lineitem   lineitems
-      #
-      # Additionally, the class-level +table_name_prefix+ is prepended and the
-      # +table_name_suffix+ is appended. So if you have "myapp_" as a prefix,
-      # the table name guess for an Invoice class becomes "myapp_invoices".
-      # Invoice::Lineitem becomes "myapp_invoice_lineitems".
-      #
-      # You can also overwrite this class method to allow for unguessable
-      # links, such as a Mouse class with a link to a "mice" table. Example:
-      #
-      #   class Mouse < ActiveRecord::Base
-      #     set_table_name "mice"
-      #   end
-      def table_name
-        reset_table_name
-      end
-
-      # Returns a quoted version of the table name, used to construct SQL statements.
-      def quoted_table_name
-        @quoted_table_name ||= connection.quote_table_name(table_name)
-      end
-
-      # Computes the table name, (re)sets it internally, and returns it.
-      def reset_table_name #:nodoc:
-        return if abstract_class?
-
-        self.table_name = compute_table_name
-      end
-
-      def full_table_name_prefix #:nodoc:
-        (parents.detect{ |p| p.respond_to?(:table_name_prefix) } || self).table_name_prefix
-      end
-
-      # Defines the column name for use with single table inheritance. Use
-      # <tt>set_inheritance_column</tt> to set a different value.
-      def inheritance_column
-        @inheritance_column ||= "type"
-      end
-
-      # Lazy-set the sequence name to the connection's default. This method
-      # is only ever called once since set_sequence_name overrides it.
-      def sequence_name #:nodoc:
-        reset_sequence_name
-      end
-
-      def reset_sequence_name #:nodoc:
-        default = connection.default_sequence_name(table_name, primary_key)
-        set_sequence_name(default)
-        default
-      end
-
-      # Sets the table name. If the value is nil or false then the value returned by the given
-      # block is used.
-      #
-      #   class Project < ActiveRecord::Base
-      #     set_table_name "project"
-      #   end
-      def set_table_name(value = nil, &block)
-        @quoted_table_name = nil
-        define_attr_method :table_name, value, &block
-        @arel_table = nil
-
-        @relation = Relation.new(self, arel_table)
-      end
-      alias :table_name= :set_table_name
-
-      # Sets the name of the inheritance column to use to the given value,
-      # or (if the value # is nil or false) to the value returned by the
-      # given block.
-      #
-      #   class Project < ActiveRecord::Base
-      #     set_inheritance_column do
-      #       original_inheritance_column + "_id"
-      #     end
-      #   end
-      def set_inheritance_column(value = nil, &block)
-        define_attr_method :inheritance_column, value, &block
-      end
-      alias :inheritance_column= :set_inheritance_column
-
-      # Sets the name of the sequence to use when generating ids to the given
-      # value, or (if the value is nil or false) to the value returned by the
-      # given block. This is required for Oracle and is useful for any
-      # database which relies on sequences for primary key generation.
-      #
-      # If a sequence name is not explicitly set when using Oracle or Firebird,
-      # it will default to the commonly used pattern of: #{table_name}_seq
-      #
-      # If a sequence name is not explicitly set when using PostgreSQL, it
-      # will discover the sequence corresponding to your primary key for you.
-      #
-      #   class Project < ActiveRecord::Base
-      #     set_sequence_name "projectseq"   # default would have been "project_seq"
-      #   end
-      def set_sequence_name(value = nil, &block)
-        define_attr_method :sequence_name, value, &block
-      end
-      alias :sequence_name= :set_sequence_name
-
-      # Indicates whether the table associated with this class exists
-      def table_exists?
-        connection.table_exists?(table_name)
-      end
-
-      # Returns an array of column objects for the table associated with this class.
-      def columns
-        if defined?(@primary_key)
-          connection_pool.primary_keys[table_name] ||= @primary_key
-        end
-
-        connection_pool.columns[table_name]
-      end
-
-      # Returns a hash of column objects for the table associated with this class.
-      def columns_hash
-        connection_pool.columns_hash[table_name]
-      end
-
-      # Returns a hash where the keys are column names and the values are
-      # default values when instantiating the AR object for this table.
-      def column_defaults
-        connection_pool.column_defaults[table_name]
-      end
-
-      # Returns an array of column names as strings.
-      def column_names
-        @column_names ||= columns.map { |column| column.name }
-      end
-
-      # Returns an array of column objects where the primary id, all columns ending in "_id" or "_count",
-      # and columns used for single table inheritance have been removed.
-      def content_columns
-        @content_columns ||= columns.reject { |c| c.primary || c.name =~ /(_id|_count)$/ || c.name == inheritance_column }
-      end
-
-      # Returns a hash of all the methods added to query each of the columns in the table with the name of the method as the key
-      # and true as the value. This makes it possible to do O(1) lookups in respond_to? to check if a given method for attribute
-      # is available.
-      def column_methods_hash #:nodoc:
-        @dynamic_methods_hash ||= column_names.inject(Hash.new(false)) do |methods, attr|
-          attr_name = attr.to_s
-          methods[attr.to_sym]       = attr_name
-          methods["#{attr}=".to_sym] = attr_name
-          methods["#{attr}?".to_sym] = attr_name
-          methods["#{attr}_before_type_cast".to_sym] = attr_name
-          methods
-        end
-      end
-
-      # Resets all the cached information about columns, which will cause them
-      # to be reloaded on the next request.
-      #
-      # The most common usage pattern for this method is probably in a migration,
-      # when just after creating a table you want to populate it with some default
-      # values, eg:
-      #
-      #  class CreateJobLevels < ActiveRecord::Migration
-      #    def self.up
-      #      create_table :job_levels do |t|
-      #        t.integer :id
-      #        t.string :name
-      #
-      #        t.timestamps
-      #      end
-      #
-      #      JobLevel.reset_column_information
-      #      %w{assistant executive manager director}.each do |type|
-      #        JobLevel.create(:name => type)
-      #      end
-      #    end
-      #
-      #    def self.down
-      #      drop_table :job_levels
-      #    end
-      #  end
-      def reset_column_information
-        connection.clear_cache!
-        undefine_attribute_methods
-        connection_pool.clear_table_cache!(table_name) if table_exists?
-
-        @column_names = @content_columns = @dynamic_methods_hash = @inheritance_column = nil
-        @arel_engine = @relation = nil
-      end
-
-      def clear_cache! # :nodoc:
-        connection_pool.clear_cache!
-      end
-
-      def attribute_method?(attribute)
-        super || (table_exists? && column_names.include?(attribute.to_s.sub(/=$/, '')))
-      end
-
-      # Returns an array of column names as strings if it's not
-      # an abstract class and table exists.
-      # Otherwise it returns an empty array.
-      def attribute_names
-        @attribute_names ||= if !abstract_class? && table_exists?
-            column_names
-          else
-            []
-          end
-      end
-
-      # Set the lookup ancestors for ActiveModel.
-      def lookup_ancestors #:nodoc:
-        klass = self
-        classes = [klass]
-        return classes if klass == ActiveRecord::Base
-
-        while klass != klass.base_class
-          classes << klass = klass.superclass
-        end
-        classes
-      end
-
-      # Set the i18n scope to overwrite ActiveModel.
-      def i18n_scope #:nodoc:
-        :activerecord
-      end
-
-      # True if this isn't a concrete subclass needing a STI type condition.
-      def descends_from_active_record?
-        if superclass.abstract_class?
-          superclass.descends_from_active_record?
-        else
-          superclass == Base || !columns_hash.include?(inheritance_column)
-        end
-      end
-
-      def finder_needs_type_condition? #:nodoc:
-        # This is like this because benchmarking justifies the strange :false stuff
-        :true == (@finder_needs_type_condition ||= descends_from_active_record? ? :false : :true)
-      end
-
-      # Returns a string like 'Post(id:integer, title:string, body:text)'
-      def inspect
-        if self == Base
-          super
-        elsif abstract_class?
-          "#{super}(abstract)"
-        elsif table_exists?
-          attr_list = columns.map { |c| "#{c.name}: #{c.type}" } * ', '
-          "#{super}(#{attr_list})"
-        else
-          "#{super}(Table doesn't exist)"
-        end
-      end
-
-      def quote_value(value, column = nil) #:nodoc:
-        connection.quote(value,column)
-      end
-
-      # Used to sanitize objects before they're used in an SQL SELECT statement. Delegates to <tt>connection.quote</tt>.
-      def sanitize(object) #:nodoc:
-        connection.quote(object)
-      end
-
-      # Overwrite the default class equality method to provide support for association proxies.
-      def ===(object)
-        object.is_a?(self)
-      end
-
-      def symbolized_base_class
-        @symbolized_base_class ||= base_class.to_s.to_sym
-      end
-
-      def symbolized_sti_name
-        @symbolized_sti_name ||= sti_name.present? ? sti_name.to_sym : symbolized_base_class
-      end
-
-      # Returns the base AR subclass that this class descends from. If A
-      # extends AR::Base, A.base_class will return A. If B descends from A
-      # through some arbitrarily deep hierarchy, B.base_class will return A.
-      #
-      # If B < A and C < B and if A is an abstract_class then both B.base_class
-      # and C.base_class would return B as the answer since A is an abstract_class.
-      def base_class
-        class_of_active_record_descendant(self)
-      end
-
-      # Set this to true if this is an abstract class (see <tt>abstract_class?</tt>).
-      attr_accessor :abstract_class
-
-      # Returns whether this class is an abstract class or not.
-      def abstract_class?
-        defined?(@abstract_class) && @abstract_class == true
-      end
-
-      def respond_to?(method_id, include_private = false)
-        if match = DynamicFinderMatch.match(method_id)
-          return true if all_attributes_exists?(match.attribute_names)
-        elsif match = DynamicScopeMatch.match(method_id)
-          return true if all_attributes_exists?(match.attribute_names)
-        end
-
-        super
-      end
-
-      def sti_name
-        store_full_sti_class ? name : name.demodulize
-      end
-
-      def arel_table
-        @arel_table ||= Arel::Table.new(table_name, arel_engine)
-      end
-
-      def arel_engine
-        @arel_engine ||= begin
-          if self == ActiveRecord::Base
-            ActiveRecord::Base
-          else
-            connection_handler.connection_pools[name] ? self : superclass.arel_engine
-          end
-        end
-      end
-
-      # Returns a scope for this class without taking into account the default_scope.
-      #
-      #   class Post < ActiveRecord::Base
-      #     def self.default_scope
-      #       where :published => true
-      #     end
-      #   end
-      #
-      #   Post.all          # Fires "SELECT * FROM posts WHERE published = true"
-      #   Post.unscoped.all # Fires "SELECT * FROM posts"
-      #
-      # This method also accepts a block meaning that all queries inside the block will
-      # not use the default_scope:
-      #
-      #   Post.unscoped {
-      #     Post.limit(10) # Fires "SELECT * FROM posts LIMIT 10"
-      #   }
-      #
-      # It is recommended to use block form of unscoped because chaining unscoped with <tt>scope</tt>
-      # does not work. Assuming that <tt>published</tt> is a <tt>scope</tt> following two statements are same.
-      #
-      # Post.unscoped.published
-      # Post.published
-      def unscoped #:nodoc:
-        block_given? ? relation.scoping { yield } : relation
-      end
-
-      def before_remove_const #:nodoc:
-        self.current_scope = nil
-      end
-
-      # Finder methods must instantiate through this method to work with the
-      # single-table inheritance model that makes it possible to create
-      # objects of different types from the same table.
-      def instantiate(record)
-        sti_class = find_sti_class(record[inheritance_column])
-        record_id = sti_class.primary_key? && record[sti_class.primary_key]
-
-        if ActiveRecord::IdentityMap.enabled? && record_id
-          if (column = sti_class.columns_hash[sti_class.primary_key]) && column.number?
-            record_id = record_id.to_i
-          end
-          if instance = IdentityMap.get(sti_class, record_id)
-            instance.reinit_with('attributes' => record)
-          else
-            instance = sti_class.allocate.init_with('attributes' => record)
-            IdentityMap.add(instance)
-          end
-        else
-          instance = sti_class.allocate.init_with('attributes' => record)
-        end
-
-        instance
-      end
-
-      private
-
-        def relation #:nodoc:
-          @relation ||= Relation.new(self, arel_table)
-
-          if finder_needs_type_condition?
-            @relation.where(type_condition).create_with(inheritance_column.to_sym => sti_name)
-          else
-            @relation
-          end
-        end
-
-        def find_sti_class(type_name)
-          if type_name.blank? || !columns_hash.include?(inheritance_column)
-            self
-          else
-            begin
-              if store_full_sti_class
-                ActiveSupport::Dependencies.constantize(type_name)
-              else
-                compute_type(type_name)
-              end
-            rescue NameError
-              raise SubclassNotFound,
-                "The single-table inheritance mechanism failed to locate the subclass: '#{type_name}'. " +
-                "This error is raised because the column '#{inheritance_column}' is reserved for storing the class in case of inheritance. " +
-                "Please rename this column if you didn't intend it to be used for storing the inheritance class " +
-                "or overwrite #{name}.inheritance_column to use another column for that information."
-            end
-          end
-        end
-
-        def construct_finder_arel(options = {}, scope = nil)
-          relation = options.is_a?(Hash) ? unscoped.apply_finder_options(options) : options
-          relation = scope.merge(relation) if scope
-          relation
-        end
-
-        def type_condition(table = arel_table)
-          sti_column = table[inheritance_column.to_sym]
-          sti_names  = ([self] + descendants).map { |model| model.sti_name }
-
-          sti_column.in(sti_names)
-        end
-
-        # Guesses the table name, but does not decorate it with prefix and suffix information.
-        def undecorated_table_name(class_name = base_class.name)
-          table_name = class_name.to_s.demodulize.underscore
-          table_name = table_name.pluralize if pluralize_table_names
-          table_name
-        end
-
-        # Computes and returns a table name according to default conventions.
-        def compute_table_name
-          base = base_class
-          if self == base
-            # Nested classes are prefixed with singular parent table name.
-            if parent < ActiveRecord::Base && !parent.abstract_class?
-              contained = parent.table_name
-              contained = contained.singularize if parent.pluralize_table_names
-              contained += '_'
-            end
-            "#{full_table_name_prefix}#{contained}#{undecorated_table_name(name)}#{table_name_suffix}"
-          else
-            # STI subclasses always use their superclass' table.
-            base.table_name
-          end
-        end
-
-        # Enables dynamic finders like <tt>User.find_by_user_name(user_name)</tt> and
-        # <tt>User.scoped_by_user_name(user_name). Refer to Dynamic attribute-based finders
-        # section at the top of this file for more detailed information.
-        #
-        # It's even possible to use all the additional parameters to +find+. For example, the
-        # full interface for +find_all_by_amount+ is actually <tt>find_all_by_amount(amount, options)</tt>.
-        #
-        # Each dynamic finder using <tt>scoped_by_*</tt> is also defined in the class after it
-        # is first invoked, so that future attempts to use it do not run through method_missing.
-        def method_missing(method_id, *arguments, &block)
-          if match = (DynamicFinderMatch.match(method_id) || DynamicScopeMatch.match(method_id))
-            attribute_names = match.attribute_names
-            super unless all_attributes_exists?(attribute_names)
-            if arguments.size < attribute_names.size
-              method_trace = "#{__FILE__}:#{__LINE__}:in `#{method_id}'"
-              backtrace = [method_trace] + caller
-              raise ArgumentError, "wrong number of arguments (#{arguments.size} for #{attribute_names.size})", backtrace
-            end
-            if match.respond_to?(:scope?) && match.scope?
-              self.class_eval <<-METHOD, __FILE__, __LINE__ + 1
-                def self.#{method_id}(*args)                                    # def self.scoped_by_user_name_and_password(*args)
-                  attributes = Hash[[:#{attribute_names.join(',:')}].zip(args)] #   attributes = Hash[[:user_name, :password].zip(args)]
-                                                                                #
-                  scoped(:conditions => attributes)                             #   scoped(:conditions => attributes)
-                end                                                             # end
-              METHOD
-              send(method_id, *arguments)
-            elsif match.finder?
-              options = arguments.extract_options!
-              relation = options.any? ? scoped(options) : scoped
-              relation.send :find_by_attributes, match, attribute_names, *arguments, &block
-            elsif match.instantiator?
-              scoped.send :find_or_instantiator_by_attributes, match, attribute_names, *arguments, &block
-            end
-          else
-            super
-          end
-        end
-
-        # Similar in purpose to +expand_hash_conditions_for_aggregates+.
-        def expand_attribute_names_for_aggregates(attribute_names)
-          attribute_names.map { |attribute_name|
-            unless (aggregation = reflect_on_aggregation(attribute_name.to_sym)).nil?
-              aggregate_mapping(aggregation).map do |field_attr, _|
-                field_attr.to_sym
-              end
-            else
-              attribute_name.to_sym
-            end
-          }.flatten
-        end
-
-        def all_attributes_exists?(attribute_names)
-          (expand_attribute_names_for_aggregates(attribute_names) -
-           column_methods_hash.keys).empty?
-        end
-
-      protected
-        # with_scope lets you apply options to inner block incrementally. It takes a hash and the keys must be
-        # <tt>:find</tt> or <tt>:create</tt>. <tt>:find</tt> parameter is <tt>Relation</tt> while
-        # <tt>:create</tt> parameters are an attributes hash.
-        #
-        #   class Article < ActiveRecord::Base
-        #     def self.create_with_scope
-        #       with_scope(:find => where(:blog_id => 1), :create => { :blog_id => 1 }) do
-        #         find(1) # => SELECT * from articles WHERE blog_id = 1 AND id = 1
-        #         a = create(1)
-        #         a.blog_id # => 1
-        #       end
-        #     end
-        #   end
-        #
-        # In nested scopings, all previous parameters are overwritten by the innermost rule, with the exception of
-        # <tt>where</tt>, <tt>includes</tt>, and <tt>joins</tt> operations in <tt>Relation</tt>, which are merged.
-        #
-        # <tt>joins</tt> operations are uniqued so multiple scopes can join in the same table without table aliasing
-        # problems. If you need to join multiple tables, but still want one of the tables to be uniqued, use the
-        # array of strings format for your joins.
-        #
-        #   class Article < ActiveRecord::Base
-        #     def self.find_with_scope
-        #       with_scope(:find => where(:blog_id => 1).limit(1), :create => { :blog_id => 1 }) do
-        #         with_scope(:find => limit(10)) do
-        #           all # => SELECT * from articles WHERE blog_id = 1 LIMIT 10
-        #         end
-        #         with_scope(:find => where(:author_id => 3)) do
-        #           all # => SELECT * from articles WHERE blog_id = 1 AND author_id = 3 LIMIT 1
-        #         end
-        #       end
-        #     end
-        #   end
-        #
-        # You can ignore any previous scopings by using the <tt>with_exclusive_scope</tt> method.
-        #
-        #   class Article < ActiveRecord::Base
-        #     def self.find_with_exclusive_scope
-        #       with_scope(:find => where(:blog_id => 1).limit(1)) do
-        #         with_exclusive_scope(:find => limit(10)) do
-        #           all # => SELECT * from articles LIMIT 10
-        #         end
-        #       end
-        #     end
-        #   end
-        #
-        # *Note*: the +:find+ scope also has effect on update and deletion methods, like +update_all+ and +delete_all+.
-        def with_scope(scope = {}, action = :merge, &block)
-          # If another Active Record class has been passed in, get its current scope
-          scope = scope.current_scope if !scope.is_a?(Relation) && scope.respond_to?(:current_scope)
-
-          previous_scope = self.current_scope
-
-          if scope.is_a?(Hash)
-            # Dup first and second level of hash (method and params).
-            scope = scope.dup
-            scope.each do |method, params|
-              scope[method] = params.dup unless params == true
-            end
-
-            scope.assert_valid_keys([ :find, :create ])
-            relation = construct_finder_arel(scope[:find] || {})
-            relation.default_scoped = true unless action == :overwrite
-
-            if previous_scope && previous_scope.create_with_value && scope[:create]
-              scope_for_create = if action == :merge
-                previous_scope.create_with_value.merge(scope[:create])
-              else
-                scope[:create]
-              end
-
-              relation = relation.create_with(scope_for_create)
-            else
-              scope_for_create = scope[:create]
-              scope_for_create ||= previous_scope.create_with_value if previous_scope
-              relation = relation.create_with(scope_for_create) if scope_for_create
-            end
-
-            scope = relation
-          end
-
-          scope = previous_scope.merge(scope) if previous_scope && action == :merge
-
-          self.current_scope = scope
-          begin
-            yield
-          ensure
-            self.current_scope = previous_scope
-          end
-        end
-
-        # Works like with_scope, but discards any nested properties.
-        def with_exclusive_scope(method_scoping = {}, &block)
-          if method_scoping.values.any? { |e| e.is_a?(ActiveRecord::Relation) }
-            raise ArgumentError, <<-MSG
-New finder API can not be used with_exclusive_scope. You can either call unscoped to get an anonymous scope not bound to the default_scope:
-
-  User.unscoped.where(:active => true)
-
-Or call unscoped with a block:
-
-  User.unscoped do
-    User.where(:active => true).all
-  end
-
-MSG
-          end
-          with_scope(method_scoping, :overwrite, &block)
-        end
-
-        def current_scope #:nodoc:
-          Thread.current["#{self}_current_scope"]
-        end
-
-        def current_scope=(scope) #:nodoc:
-          Thread.current["#{self}_current_scope"] = scope
-        end
-
-        # Use this macro in your model to set a default scope for all operations on
-        # the model.
-        #
-        #   class Article < ActiveRecord::Base
-        #     default_scope where(:published => true)
-        #   end
-        #
-        #   Article.all # => SELECT * FROM articles WHERE published = true
-        #
-        # The <tt>default_scope</tt> is also applied while creating/building a record. It is not
-        # applied while updating a record.
-        #
-        #   Article.new.published    # => true
-        #   Article.create.published # => true
-        #
-        # You can also use <tt>default_scope</tt> with a block, in order to have it lazily evaluated:
-        #
-        #   class Article < ActiveRecord::Base
-        #     default_scope { where(:published_at => Time.now - 1.week) }
-        #   end
-        #
-        # (You can also pass any object which responds to <tt>call</tt> to the <tt>default_scope</tt>
-        # macro, and it will be called when building the default scope.)
-        #
-        # If you use multiple <tt>default_scope</tt> declarations in your model then they will
-        # be merged together:
-        #
-        #   class Article < ActiveRecord::Base
-        #     default_scope where(:published => true)
-        #     default_scope where(:rating => 'G')
-        #   end
-        #
-        #   Article.all # => SELECT * FROM articles WHERE published = true AND rating = 'G'
-        #
-        # This is also the case with inheritance and module includes where the parent or module
-        # defines a <tt>default_scope</tt> and the child or including class defines a second one.
-        #
-        # If you need to do more complex things with a default scope, you can alternatively
-        # define it as a class method:
-        #
-        #   class Article < ActiveRecord::Base
-        #     def self.default_scope
-        #       # Should return a scope, you can call 'super' here etc.
-        #     end
-        #   end
-        def default_scope(scope = {})
-          scope = Proc.new if block_given?
-          self.default_scopes = default_scopes + [scope]
-        end
-
-        def build_default_scope #:nodoc:
-          if method(:default_scope).owner != Base.singleton_class
-            evaluate_default_scope { default_scope }
-          elsif default_scopes.any?
-            evaluate_default_scope do
-              default_scopes.inject(relation) do |default_scope, scope|
-                if scope.is_a?(Hash)
-                  default_scope.apply_finder_options(scope)
-                elsif !scope.is_a?(Relation) && scope.respond_to?(:call)
-                  default_scope.merge(scope.call)
-                else
-                  default_scope.merge(scope)
-                end
-              end
-            end
-          end
-        end
-
-        def ignore_default_scope? #:nodoc:
-          Thread.current["#{self}_ignore_default_scope"]
-        end
-
-        def ignore_default_scope=(ignore) #:nodoc:
-          Thread.current["#{self}_ignore_default_scope"] = ignore
-        end
-
-        # The ignore_default_scope flag is used to prevent an infinite recursion situation where
-        # a default scope references a scope which has a default scope which references a scope...
-        def evaluate_default_scope
-          return if ignore_default_scope?
-
-          begin
-            self.ignore_default_scope = true
-            yield
-          ensure
-            self.ignore_default_scope = false
-          end
-        end
-
-        # Returns the class type of the record using the current module as a prefix. So descendants of
-        # MyApp::Business::Account would appear as MyApp::Business::AccountSubclass.
-        def compute_type(type_name)
-          if type_name.match(/^::/)
-            # If the type is prefixed with a scope operator then we assume that
-            # the type_name is an absolute reference.
-            ActiveSupport::Dependencies.constantize(type_name)
-          else
-            # Build a list of candidates to search for
-            candidates = []
-            name.scan(/::|$/) { candidates.unshift "#{$`}::#{type_name}" }
-            candidates << type_name
-
-            candidates.each do |candidate|
-              begin
-                constant = ActiveSupport::Dependencies.constantize(candidate)
-                return constant if candidate == constant.to_s
-              rescue NameError => e
-                # We don't want to swallow NoMethodError < NameError errors
-                raise e unless e.instance_of?(NameError)
-              end
-            end
-
-            raise NameError, "uninitialized constant #{candidates.first}"
-          end
-        end
-
-        # Returns the class descending directly from ActiveRecord::Base or an
-        # abstract class, if any, in the inheritance hierarchy.
-        def class_of_active_record_descendant(klass)
-          if klass == Base || klass.superclass == Base || klass.superclass.abstract_class?
-            klass
-          elsif klass.superclass.nil?
-            raise ActiveRecordError, "#{name} doesn't belong in a hierarchy descending from ActiveRecord"
-          else
-            class_of_active_record_descendant(klass.superclass)
-          end
-        end
-
-        # Accepts an array, hash, or string of SQL conditions and sanitizes
-        # them into a valid SQL fragment for a WHERE clause.
-        #   ["name='%s' and group_id='%s'", "foo'bar", 4]  returns  "name='foo''bar' and group_id='4'"
-        #   { :name => "foo'bar", :group_id => 4 }  returns "name='foo''bar' and group_id='4'"
-        #   "name='foo''bar' and group_id='4'" returns "name='foo''bar' and group_id='4'"
-        def sanitize_sql_for_conditions(condition, table_name = self.table_name)
-          return nil if condition.blank?
-
-          case condition
-            when Array; sanitize_sql_array(condition)
-            when Hash;  sanitize_sql_hash_for_conditions(condition, table_name)
-            else        condition
-          end
-        end
-        alias_method :sanitize_sql, :sanitize_sql_for_conditions
-
-        # Accepts an array, hash, or string of SQL conditions and sanitizes
-        # them into a valid SQL fragment for a SET clause.
-        #   { :name => nil, :group_id => 4 }  returns "name = NULL , group_id='4'"
-        def sanitize_sql_for_assignment(assignments)
-          case assignments
-            when Array; sanitize_sql_array(assignments)
-            when Hash;  sanitize_sql_hash_for_assignment(assignments)
-            else        assignments
-          end
-        end
-
-        def aggregate_mapping(reflection)
-          mapping = reflection.options[:mapping] || [reflection.name, reflection.name]
-          mapping.first.is_a?(Array) ? mapping : [mapping]
-        end
-
-        # Accepts a hash of SQL conditions and replaces those attributes
-        # that correspond to a +composed_of+ relationship with their expanded
-        # aggregate attribute values.
-        # Given:
-        #     class Person < ActiveRecord::Base
-        #       composed_of :address, :class_name => "Address",
-        #         :mapping => [%w(address_street street), %w(address_city city)]
-        #     end
-        # Then:
-        #     { :address => Address.new("813 abc st.", "chicago") }
-        #       # => { :address_street => "813 abc st.", :address_city => "chicago" }
-        def expand_hash_conditions_for_aggregates(attrs)
-          expanded_attrs = {}
-          attrs.each do |attr, value|
-            unless (aggregation = reflect_on_aggregation(attr.to_sym)).nil?
-              mapping = aggregate_mapping(aggregation)
-              mapping.each do |field_attr, aggregate_attr|
-                if mapping.size == 1 && !value.respond_to?(aggregate_attr)
-                  expanded_attrs[field_attr] = value
-                else
-                  expanded_attrs[field_attr] = value.send(aggregate_attr)
-                end
-              end
-            else
-              expanded_attrs[attr] = value
-            end
-          end
-          expanded_attrs
-        end
-
-        # Sanitizes a hash of attribute/value pairs into SQL conditions for a WHERE clause.
-        #   { :name => "foo'bar", :group_id => 4 }
-        #     # => "name='foo''bar' and group_id= 4"
-        #   { :status => nil, :group_id => [1,2,3] }
-        #     # => "status IS NULL and group_id IN (1,2,3)"
-        #   { :age => 13..18 }
-        #     # => "age BETWEEN 13 AND 18"
-        #   { 'other_records.id' => 7 }
-        #     # => "`other_records`.`id` = 7"
-        #   { :other_records => { :id => 7 } }
-        #     # => "`other_records`.`id` = 7"
-        # And for value objects on a composed_of relationship:
-        #   { :address => Address.new("123 abc st.", "chicago") }
-        #     # => "address_street='123 abc st.' and address_city='chicago'"
-        def sanitize_sql_hash_for_conditions(attrs, default_table_name = self.table_name)
-          attrs = expand_hash_conditions_for_aggregates(attrs)
-
-          table = Arel::Table.new(table_name).alias(default_table_name)
-          PredicateBuilder.build_from_hash(arel_engine, attrs, table).map { |b|
-            connection.visitor.accept b
-          }.join(' AND ')
-        end
-        alias_method :sanitize_sql_hash, :sanitize_sql_hash_for_conditions
-
-        # Sanitizes a hash of attribute/value pairs into SQL conditions for a SET clause.
-        #   { :status => nil, :group_id => 1 }
-        #     # => "status = NULL , group_id = 1"
-        def sanitize_sql_hash_for_assignment(attrs)
-          attrs.map do |attr, value|
-            "#{connection.quote_column_name(attr)} = #{quote_bound_value(value)}"
-          end.join(', ')
-        end
-
-        # Accepts an array of conditions. The array has each value
-        # sanitized and interpolated into the SQL statement.
-        #   ["name='%s' and group_id='%s'", "foo'bar", 4]  returns  "name='foo''bar' and group_id='4'"
-        def sanitize_sql_array(ary)
-          statement, *values = ary
-          if values.first.is_a?(Hash) && statement =~ /:\w+/
-            replace_named_bind_variables(statement, values.first)
-          elsif statement.include?('?')
-            replace_bind_variables(statement, values)
-          elsif statement.blank?
-            statement
-          else
-            statement % values.collect { |value| connection.quote_string(value.to_s) }
-          end
-        end
-
-        alias_method :sanitize_conditions, :sanitize_sql
-
-        def replace_bind_variables(statement, values) #:nodoc:
-          raise_if_bind_arity_mismatch(statement, statement.count('?'), values.size)
-          bound = values.dup
-          c = connection
-          statement.gsub('?') { quote_bound_value(bound.shift, c) }
-        end
-
-        def replace_named_bind_variables(statement, bind_vars) #:nodoc:
-          statement.gsub(/(:?):([a-zA-Z]\w*)/) do
-            if $1 == ':' # skip postgresql casts
-              $& # return the whole match
-            elsif bind_vars.include?(match = $2.to_sym)
-              quote_bound_value(bind_vars[match])
-            else
-              raise PreparedStatementInvalid, "missing value for :#{match} in #{statement}"
-            end
-          end
-        end
-
-        def expand_range_bind_variables(bind_vars) #:nodoc:
-          expanded = []
-
-          bind_vars.each do |var|
-            next if var.is_a?(Hash)
-
-            if var.is_a?(Range)
-              expanded << var.first
-              expanded << var.last
-            else
-              expanded << var
-            end
-          end
-
-          expanded
-        end
-
-        def quote_bound_value(value, c = connection) #:nodoc:
-          if value.respond_to?(:map) && !value.acts_like?(:string)
-            if value.respond_to?(:empty?) && value.empty?
-              c.quote(nil)
-            else
-              value.map { |v| c.quote(v) }.join(',')
-            end
-          else
-            c.quote(value)
-          end
-        end
-
-        def raise_if_bind_arity_mismatch(statement, expected, provided) #:nodoc:
-          unless expected == provided
-            raise PreparedStatementInvalid, "wrong number of bind variables (#{provided} for #{expected}) in: #{statement}"
-          end
-        end
-
-        def encode_quoted_value(value) #:nodoc:
-          quoted_value = connection.quote(value)
-          quoted_value = "'#{quoted_value[1..-2].gsub(/\'/, "\\\\'")}'" if quoted_value.include?("\\\'") # (for ruby mode) "
-          quoted_value
-        end
-    end
-
-    public
-      # New objects can be instantiated as either empty (pass no construction parameter) or pre-set with
-      # attributes but not yet saved (pass a hash with key names matching the associated table column names).
-      # In both instances, valid attribute keys are determined by the column names of the associated table --
-      # hence you can't have attributes that aren't part of the table columns.
-      #
-      # +initialize+ respects mass-assignment security and accepts either +:as+ or +:without_protection+ options
-      # in the +options+ parameter.
-      #
-      # ==== Examples
-      #   # Instantiates a single new object
-      #   User.new(:first_name => 'Jamie')
-      #
-      #   # Instantiates a single new object using the :admin mass-assignment security role
-      #   User.new({ :first_name => 'Jamie', :is_admin => true }, :as => :admin)
-      #
-      #   # Instantiates a single new object bypassing mass-assignment security
-      #   User.new({ :first_name => 'Jamie', :is_admin => true }, :without_protection => true)
-      def initialize(attributes = nil, options = {})
-        @attributes = attributes_from_column_definition
-        @association_cache = {}
-        @aggregation_cache = {}
-        @attributes_cache = {}
-        @new_record = true
-        @readonly = false
-        @destroyed = false
-        @marked_for_destruction = false
-        @previously_changed = {}
-        @changed_attributes = {}
-        @relation = nil
-
-        ensure_proper_type
-        set_serialized_attributes
-
-        populate_with_current_scope_attributes
-
-        assign_attributes(attributes, options) if attributes
-
-        yield self if block_given?
-        run_callbacks :initialize
-      end
-
-      # Populate +coder+ with attributes about this record that should be
-      # serialized. The structure of +coder+ defined in this method is
-      # guaranteed to match the structure of +coder+ passed to the +init_with+
-      # method.
-      #
-      # Example:
-      #
-      #   class Post < ActiveRecord::Base
-      #   end
-      #   coder = {}
-      #   Post.new.encode_with(coder)
-      #   coder # => { 'id' => nil, ... }
-      def encode_with(coder)
-        coder['attributes'] = attributes
-      end
-
-      # Initialize an empty model object from +coder+. +coder+ must contain
-      # the attributes necessary for initializing an empty model object. For
-      # example:
-      #
-      #   class Post < ActiveRecord::Base
-      #   end
-      #
-      #   post = Post.allocate
-      #   post.init_with('attributes' => { 'title' => 'hello world' })
-      #   post.title # => 'hello world'
-      def init_with(coder)
-        @attributes = coder['attributes']
-        @relation = nil
-
-        set_serialized_attributes
-
-        @attributes_cache, @previously_changed, @changed_attributes = {}, {}, {}
-        @association_cache = {}
-        @aggregation_cache = {}
-        @readonly = @destroyed = @marked_for_destruction = false
-        @new_record = false
-        run_callbacks :find
-        run_callbacks :initialize
-
-        self
-      end
-
-      # Returns a String, which Action Pack uses for constructing an URL to this
-      # object. The default implementation returns this record's id as a String,
-      # or nil if this record's unsaved.
-      #
-      # For example, suppose that you have a User model, and that you have a
-      # <tt>resources :users</tt> route. Normally, +user_path+ will
-      # construct a path with the user object's 'id' in it:
-      #
-      #   user = User.find_by_name('Phusion')
-      #   user_path(user)  # => "/users/1"
-      #
-      # You can override +to_param+ in your model to make +user_path+ construct
-      # a path using the user's name instead of the user's id:
-      #
-      #   class User < ActiveRecord::Base
-      #     def to_param  # overridden
-      #       name
-      #     end
-      #   end
-      #
-      #   user = User.find_by_name('Phusion')
-      #   user_path(user)  # => "/users/Phusion"
-      def to_param
-        # We can't use alias_method here, because method 'id' optimizes itself on the fly.
-        id && id.to_s # Be sure to stringify the id for routes
-      end
-
-      # Returns a cache key that can be used to identify this record.
-      #
-      # ==== Examples
-      #
-      #   Product.new.cache_key     # => "products/new"
-      #   Product.find(5).cache_key # => "products/5" (updated_at not available)
-      #   Person.find(5).cache_key  # => "people/5-20071224150000" (updated_at available)
-      def cache_key
-        case
-        when new_record?
-          "#{self.class.model_name.cache_key}/new"
-        when timestamp = self[:updated_at]
-          timestamp = timestamp.utc.to_s(:number)
-          "#{self.class.model_name.cache_key}/#{id}-#{timestamp}"
-        else
-          "#{self.class.model_name.cache_key}/#{id}"
-        end
-      end
-
-      def quoted_id #:nodoc:
-        quote_value(id, column_for_attribute(self.class.primary_key))
-      end
-
-      # Returns true if the given attribute is in the attributes hash
-      def has_attribute?(attr_name)
-        @attributes.has_key?(attr_name.to_s)
-      end
-
-      # Returns an array of names for the attributes available on this object.
-      def attribute_names
-        @attributes.keys
-      end
-
-      # Allows you to set all the attributes at once by passing in a hash with keys
-      # matching the attribute names (which again matches the column names).
-      #
-      # If any attributes are protected by either +attr_protected+ or
-      # +attr_accessible+ then only settable attributes will be assigned.
-      #
-      #   class User < ActiveRecord::Base
-      #     attr_protected :is_admin
-      #   end
-      #
-      #   user = User.new
-      #   user.attributes = { :username => 'Phusion', :is_admin => true }
-      #   user.username   # => "Phusion"
-      #   user.is_admin?  # => false
-      def attributes=(new_attributes)
-        return unless new_attributes.is_a?(Hash)
-
-        assign_attributes(new_attributes)
-      end
-
-      # Allows you to set all the attributes for a particular mass-assignment
-      # security role by passing in a hash of attributes with keys matching
-      # the attribute names (which again matches the column names) and the role
-      # name using the :as option.
-      #
-      # To bypass mass-assignment security you can use the :without_protection => true
-      # option.
-      #
-      #   class User < ActiveRecord::Base
-      #     attr_accessible :name
-      #     attr_accessible :name, :is_admin, :as => :admin
-      #   end
-      #
-      #   user = User.new
-      #   user.assign_attributes({ :name => 'Josh', :is_admin => true })
-      #   user.name       # => "Josh"
-      #   user.is_admin?  # => false
-      #
-      #   user = User.new
-      #   user.assign_attributes({ :name => 'Josh', :is_admin => true }, :as => :admin)
-      #   user.name       # => "Josh"
-      #   user.is_admin?  # => true
-      #
-      #   user = User.new
-      #   user.assign_attributes({ :name => 'Josh', :is_admin => true }, :without_protection => true)
-      #   user.name       # => "Josh"
-      #   user.is_admin?  # => true
-      def assign_attributes(new_attributes, options = {})
-        return unless new_attributes
-
-        attributes = new_attributes.stringify_keys
-        multi_parameter_attributes = []
-        @mass_assignment_options = options
-
-        unless options[:without_protection]
-          attributes = sanitize_for_mass_assignment(attributes, mass_assignment_role)
-        end
-
-        attributes.each do |k, v|
-          if k.include?("(")
-            multi_parameter_attributes << [ k, v ]
-          elsif respond_to?("#{k}=")
-            send("#{k}=", v)
-          else
-            raise(UnknownAttributeError, "unknown attribute: #{k}")
-          end
-        end
-
-        @mass_assignment_options = nil
-        assign_multiparameter_attributes(multi_parameter_attributes)
-      end
-
-      # Returns a hash of all the attributes with their names as keys and the values of the attributes as values.
-      def attributes
-        Hash[@attributes.map { |name, _| [name, read_attribute(name)] }]
-      end
-
-      # Returns an <tt>#inspect</tt>-like string for the value of the
-      # attribute +attr_name+. String attributes are truncated upto 50
-      # characters, and Date and Time attributes are returned in the
-      # <tt>:db</tt> format. Other attributes return the value of
-      # <tt>#inspect</tt> without modification.
-      #
-      #   person = Person.create!(:name => "David Heinemeier Hansson " * 3)
-      #
-      #   person.attribute_for_inspect(:name)
-      #   # => '"David Heinemeier Hansson David Heinemeier Hansson D..."'
-      #
-      #   person.attribute_for_inspect(:created_at)
-      #   # => '"2009-01-12 04:48:57"'
-      def attribute_for_inspect(attr_name)
-        value = read_attribute(attr_name)
-
-        if value.is_a?(String) && value.length > 50
-          "#{value[0..50]}...".inspect
-        elsif value.is_a?(Date) || value.is_a?(Time)
-          %("#{value.to_s(:db)}")
-        else
-          value.inspect
-        end
-      end
-
-      # Returns true if the specified +attribute+ has been set by the user or by a database load and is neither
-      # nil nor empty? (the latter only applies to objects that respond to empty?, most notably Strings).
-      def attribute_present?(attribute)
-        !_read_attribute(attribute).blank?
-      end
-
-      # Returns the column object for the named attribute.
-      def column_for_attribute(name)
-        self.class.columns_hash[name.to_s]
-      end
-
-      # Returns true if +comparison_object+ is the same exact object, or +comparison_object+
-      # is of the same type and +self+ has an ID and it is equal to +comparison_object.id+.
-      #
-      # Note that new records are different from any other record by definition, unless the
-      # other record is the receiver itself. Besides, if you fetch existing records with
-      # +select+ and leave the ID out, you're on your own, this predicate will return false.
-      #
-      # Note also that destroying a record preserves its ID in the model instance, so deleted
-      # models are still comparable.
-      def ==(comparison_object)
-        super ||
-          comparison_object.instance_of?(self.class) &&
-          id.present? &&
-          comparison_object.id == id
-      end
-      alias :eql? :==
-
-      # Delegates to id in order to allow two records of the same type and id to work with something like:
-      #   [ Person.find(1), Person.find(2), Person.find(3) ] & [ Person.find(1), Person.find(4) ] # => [ Person.find(1) ]
-      def hash
-        id.hash
-      end
-
-      # Freeze the attributes hash such that associations are still accessible, even on destroyed records.
-      def freeze
-        @attributes.freeze; self
-      end
-
-      # Returns +true+ if the attributes hash has been frozen.
-      def frozen?
-        @attributes.frozen?
-      end
-
-      # Allows sort on objects
-      def <=>(other_object)
-        if other_object.is_a?(self.class)
-          self.to_key <=> other_object.to_key
-        else
-          nil
-        end
-      end
-
-      # Backport dup from 1.9 so that initialize_dup() gets called
-      unless Object.respond_to?(:initialize_dup)
-        def dup # :nodoc:
-          copy = super
-          copy.initialize_dup(self)
-          copy
-        end
-      end
-
-      # Duped objects have no id assigned and are treated as new records. Note
-      # that this is a "shallow" copy as it copies the object's attributes
-      # only, not its associations. The extent of a "deep" copy is application
-      # specific and is therefore left to the application to implement according
-      # to its need.
-      # The dup method does not preserve the timestamps (created|updated)_(at|on).
-      def initialize_dup(other)
-        cloned_attributes = other.clone_attributes(:read_attribute_before_type_cast)
-        cloned_attributes.delete(self.class.primary_key)
-
-        @attributes = cloned_attributes
-
-        _run_after_initialize_callbacks if respond_to?(:_run_after_initialize_callbacks)
-
-        @changed_attributes = {}
-        attributes_from_column_definition.each do |attr, orig_value|
-          @changed_attributes[attr] = orig_value if field_changed?(attr, orig_value, @attributes[attr])
-        end
-
-        @aggregation_cache = {}
-        @association_cache = {}
-        @attributes_cache = {}
-        @new_record  = true
-
-        ensure_proper_type
-        populate_with_current_scope_attributes
-        super
-      end
-
-      # Returns +true+ if the record is read only. Records loaded through joins with piggy-back
-      # attributes will be marked as read only since they cannot be saved.
-      def readonly?
-        @readonly
-      end
-
-      # Marks this record as read only.
-      def readonly!
-        @readonly = true
-      end
-
-      # Returns the contents of the record as a nicely formatted string.
-      def inspect
-        inspection = if @attributes
-                       self.class.column_names.collect { |name|
-                         if has_attribute?(name)
-                           "#{name}: #{attribute_for_inspect(name)}"
-                         end
-                       }.compact.join(", ")
-                     else
-                       "not initialized"
-                     end
-        "#<#{self.class} #{inspection}>"
-      end
-
-    protected
-      def clone_attributes(reader_method = :read_attribute, attributes = {})
-        attribute_names.each do |name|
-          attributes[name] = clone_attribute_value(reader_method, name)
-        end
-        attributes
-      end
-
-      def clone_attribute_value(reader_method, attribute_name)
-        value = send(reader_method, attribute_name)
-        value.duplicable? ? value.clone : value
-      rescue TypeError, NoMethodError
-        value
-      end
-
-      def mass_assignment_options
-        @mass_assignment_options ||= {}
-      end
-
-      def mass_assignment_role
-        mass_assignment_options[:as] || :default
-      end
-
-    private
-
-      # Under Ruby 1.9, Array#flatten will call #to_ary (recursively) on each of the elements
-      # of the array, and then rescues from the possible NoMethodError. If those elements are
-      # ActiveRecord::Base's, then this triggers the various method_missing's that we have,
-      # which significantly impacts upon performance.
-      #
-      # So we can avoid the method_missing hit by explicitly defining #to_ary as nil here.
-      #
-      # See also http://tenderlovemaking.com/2011/06/28/til-its-ok-to-return-nil-from-to_ary/
-      def to_ary # :nodoc:
-        nil
-      end
-
-      def set_serialized_attributes
-        sattrs = self.class.serialized_attributes
-
-        sattrs.each do |key, coder|
-          @attributes[key] = coder.load @attributes[key] if @attributes.key?(key)
-        end
-      end
-
-      # Sets the attribute used for single table inheritance to this class name if this is not the
-      # ActiveRecord::Base descendant.
-      # Considering the hierarchy Reply < Message < ActiveRecord::Base, this makes it possible to
-      # do Reply.new without having to set <tt>Reply[Reply.inheritance_column] = "Reply"</tt> yourself.
-      # No such attribute would be set for objects of the Message class in that example.
-      def ensure_proper_type
-        klass = self.class
-        if klass.finder_needs_type_condition?
-          write_attribute(klass.inheritance_column, klass.sti_name)
-        end
-      end
-
-      # The primary key and inheritance column can never be set by mass-assignment for security reasons.
-      def self.attributes_protected_by_default
-        default = [ inheritance_column ]
-        default << primary_key if primary_key?
-        default << 'id' unless primary_key? && primary_key == 'id'
-        default
-      end
-
-      # Returns a copy of the attributes hash where all the values have been safely quoted for use in
-      # an Arel insert/update method.
-      def arel_attributes_values(include_primary_key = true, include_readonly_attributes = true, attribute_names = @attributes.keys)
-        attrs      = {}
-        klass      = self.class
-        arel_table = klass.arel_table
-
-        attribute_names.each do |name|
-          if (column = column_for_attribute(name)) && (include_primary_key || !column.primary)
-
-            if include_readonly_attributes || (!include_readonly_attributes && !self.class.readonly_attributes.include?(name))
-
-              value = if coder = klass.serialized_attributes[name]
-                        coder.dump @attributes[name]
-                      else
-                        # FIXME: we need @attributes to be used consistently.
-                        # If the values stored in @attributes were already type
-                        # casted, this code could be simplified
-                        read_attribute(name)
-                      end
-
-              attrs[arel_table[name]] = value
-            end
-          end
-        end
-        attrs
-      end
-
-      # Quote strings appropriately for SQL statements.
-      def quote_value(value, column = nil)
-        self.class.connection.quote(value, column)
-      end
-
-      # Instantiates objects for all attribute classes that needs more than one constructor parameter. This is done
-      # by calling new on the column type or aggregation type (through composed_of) object with these parameters.
-      # So having the pairs written_on(1) = "2004", written_on(2) = "6", written_on(3) = "24", will instantiate
-      # written_on (a date type) with Date.new("2004", "6", "24"). You can also specify a typecast character in the
-      # parentheses to have the parameters typecasted before they're used in the constructor. Use i for Fixnum,
-      # f for Float, s for String, and a for Array. If all the values for a given attribute are empty, the
-      # attribute will be set to nil.
-      def assign_multiparameter_attributes(pairs)
-        execute_callstack_for_multiparameter_attributes(
-          extract_callstack_for_multiparameter_attributes(pairs)
-        )
-      end
-
-      def instantiate_time_object(name, values)
-        if self.class.send(:create_time_zone_conversion_attribute?, name, column_for_attribute(name))
-          Time.zone.local(*values)
-        else
-          Time.time_with_datetime_fallback(@@default_timezone, *values)
-        end
-      end
-
-      def execute_callstack_for_multiparameter_attributes(callstack)
-        errors = []
-        callstack.each do |name, values_with_empty_parameters|
-          begin
-            send(name + "=", read_value_from_parameter(name, values_with_empty_parameters))
-          rescue => ex
-            errors << AttributeAssignmentError.new("error on assignment #{values_with_empty_parameters.values.inspect} to #{name}", ex, name)
-          end
-        end
-        unless errors.empty?
-          raise MultiparameterAssignmentErrors.new(errors), "#{errors.size} error(s) on assignment of multiparameter attributes"
-        end
-      end
-
-      def read_value_from_parameter(name, values_hash_from_param)
-        klass = (self.class.reflect_on_aggregation(name.to_sym) || column_for_attribute(name)).klass
-        if values_hash_from_param.values.all?{|v|v.nil?}
-          nil
-        elsif klass == Time
-          read_time_parameter_value(name, values_hash_from_param)
-        elsif klass == Date
-          read_date_parameter_value(name, values_hash_from_param)
-        else
-          read_other_parameter_value(klass, name, values_hash_from_param)
-        end
-      end
-
-      def read_time_parameter_value(name, values_hash_from_param)
-        # If Date bits were not provided, error
-        raise "Missing Parameter" if [1,2,3].any?{|position| !values_hash_from_param.has_key?(position)}
-        max_position = extract_max_param_for_multiparameter_attributes(values_hash_from_param, 6)
-        # If Date bits were provided but blank, then return nil
-        return nil if (1..3).any? {|position| values_hash_from_param[position].blank?}
-
-        set_values = (1..max_position).collect{|position| values_hash_from_param[position] }
-        # If Time bits are not there, then default to 0
-        (3..5).each {|i| set_values[i] = set_values[i].blank? ? 0 : set_values[i]}
-        instantiate_time_object(name, set_values)
-      end
-
-      def read_date_parameter_value(name, values_hash_from_param)
-        return nil if (1..3).any? {|position| values_hash_from_param[position].blank?}
-        set_values = [values_hash_from_param[1], values_hash_from_param[2], values_hash_from_param[3]]
-        begin
-          Date.new(*set_values)
-        rescue ArgumentError # if Date.new raises an exception on an invalid date
-          instantiate_time_object(name, set_values).to_date # we instantiate Time object and convert it back to a date thus using Time's logic in handling invalid dates
-        end
-      end
-
-      def read_other_parameter_value(klass, name, values_hash_from_param)
-        max_position = extract_max_param_for_multiparameter_attributes(values_hash_from_param)
-        values = (1..max_position).collect do |position|
-          raise "Missing Parameter" if !values_hash_from_param.has_key?(position)
-          values_hash_from_param[position]
-        end
-        klass.new(*values)
-      end
-
-      def extract_max_param_for_multiparameter_attributes(values_hash_from_param, upper_cap = 100)
-        [values_hash_from_param.keys.max,upper_cap].min
-      end
-
-      def extract_callstack_for_multiparameter_attributes(pairs)
-        attributes = { }
-
-        pairs.each do |pair|
-          multiparameter_name, value = pair
-          attribute_name = multiparameter_name.split("(").first
-          attributes[attribute_name] = {} unless attributes.include?(attribute_name)
-
-          parameter_value = value.empty? ? nil : type_cast_attribute_value(multiparameter_name, value)
-          attributes[attribute_name][find_parameter_position(multiparameter_name)] ||= parameter_value
-        end
-
-        attributes
-      end
-
-      def type_cast_attribute_value(multiparameter_name, value)
-        multiparameter_name =~ /\([0-9]*([if])\)/ ? value.send("to_" + $1) : value
-      end
-
-      def find_parameter_position(multiparameter_name)
-        multiparameter_name.scan(/\(([0-9]*).*\)/).first.first.to_i
-      end
-
-      # Returns a comma-separated pair list, like "key1 = val1, key2 = val2".
-      def comma_pair_list(hash)
-        hash.map { |k,v| "#{k} = #{v}" }.join(", ")
-      end
-
-      def quote_columns(quoter, hash)
-        Hash[hash.map { |name, value| [quoter.quote_column_name(name), value] }]
-      end
-
-      def quoted_comma_pair_list(quoter, hash)
-        comma_pair_list(quote_columns(quoter, hash))
-      end
-
-      def convert_number_column_value(value)
-        if value == false
-          0
-        elsif value == true
-          1
-        elsif value.is_a?(String) && value.blank?
-          nil
-        else
-          value
-        end
-      end
-
-      def populate_with_current_scope_attributes
-        return unless self.class.scope_attributes?
-
-        self.class.scope_attributes.each do |att,value|
-          send("#{att}=", value) if respond_to?("#{att}=")
-        end
-      end
-  end
-
-  Base.class_eval do
-    include ActiveRecord::Persistence
-    extend ActiveModel::Naming
-    extend QueryCache::ClassMethods
-    extend ActiveSupport::Benchmarkable
-    extend ActiveSupport::DescendantsTracker
-
-    include ActiveModel::Conversion
-    include Validations
-    extend CounterCache
-    include Locking::Optimistic, Locking::Pessimistic
-    include AttributeMethods
-    include AttributeMethods::Read, AttributeMethods::Write, AttributeMethods::BeforeTypeCast, AttributeMethods::Query
-    include AttributeMethods::PrimaryKey
-    include AttributeMethods::TimeZoneConversion
-    include AttributeMethods::Dirty
-    include ActiveModel::MassAssignmentSecurity
-    include Callbacks, ActiveModel::Observing, Timestamp
-    include Associations, NamedScope
-    include IdentityMap
-    include ActiveModel::SecurePassword
-
-    # AutosaveAssociation needs to be included before Transactions, because we want
-    # #save_with_autosave_associations to be wrapped inside a transaction.
-    include AutosaveAssociation, NestedAttributes
-    include Aggregations, Transactions, Reflection, Serialization
-
-    NilClass.add_whiner(self) if NilClass.respond_to?(:add_whiner)
-
-    # Returns the value of the attribute identified by <tt>attr_name</tt> after it has been typecast (for example,
-    # "2004-12-12" in a data column is cast to a date object, like Date.new(2004, 12, 12)).
-    # (Alias for the protected read_attribute method).
-    alias [] read_attribute
-
-    # Updates the attribute identified by <tt>attr_name</tt> with the specified +value+.
-    # (Alias for the protected write_attribute method).
-    alias []= write_attribute
-
-    public :[], :[]=
+    include ActiveRecord::Model
   end
 end
 
-require 'active_record/connection_adapters/abstract/connection_specification'
-ActiveSupport.run_load_hooks(:active_record, ActiveRecord::Base)
+ActiveSupport.run_load_hooks(:active_record, ActiveRecord::Model::DeprecationProxy)
diff --git a/activerecord/lib/active_record/callbacks.rb b/activerecord/lib/active_record/callbacks.rb
index a175bf003c..8b2fc69b00 100644
--- a/activerecord/lib/active_record/callbacks.rb
+++ b/activerecord/lib/active_record/callbacks.rb
@@ -25,7 +25,7 @@ module ActiveRecord
   # Check out <tt>ActiveRecord::Transactions</tt> for more details about <tt>after_commit</tt> and
   # <tt>after_rollback</tt>.
   #
-  # Lastly an <tt>after_find</tt> and <tt>after_initialize</tt> callback is triggered for each object that 
+  # Lastly an <tt>after_find</tt> and <tt>after_initialize</tt> callback is triggered for each object that
   # is found and instantiated by a finder, with <tt>after_initialize</tt> being triggered after new objects
   # are instantiated as well.
   #
@@ -215,24 +215,48 @@ module ActiveRecord
   # instead of quietly returning +false+.
   #
   # == Debugging callbacks
-  # 
-  # The callback chain is accessible via the <tt>_*_callbacks</tt> method on an object. ActiveModel Callbacks support 
+  #
+  # The callback chain is accessible via the <tt>_*_callbacks</tt> method on an object. ActiveModel Callbacks support
   # <tt>:before</tt>, <tt>:after</tt> and <tt>:around</tt> as values for the <tt>kind</tt> property. The <tt>kind</tt> property
   # defines what part of the chain the callback runs in.
-  # 
-  # To find all callbacks in the before_save callback chain: 
-  # 
+  #
+  # To find all callbacks in the before_save callback chain:
+  #
   #   Topic._save_callbacks.select { |cb| cb.kind.eql?(:before) }
-  # 
+  #
   # Returns an array of callback objects that form the before_save chain.
-  # 
+  #
   # To further check if the before_save chain contains a proc defined as <tt>rest_when_dead</tt> use the <tt>filter</tt> property of the callback object:
-  # 
+  #
   #   Topic._save_callbacks.select { |cb| cb.kind.eql?(:before) }.collect(&:filter).include?(:rest_when_dead)
-  # 
+  #
   # Returns true or false depending on whether the proc is contained in the before_save callback chain on a Topic model.
-  # 
+  #
   module Callbacks
+    # We can't define callbacks directly on ActiveRecord::Model because
+    # it is a module. So we queue up the definitions and execute them
+    # when ActiveRecord::Model is included.
+    module Register #:nodoc:
+      def self.extended(base)
+        base.config_attribute :_callbacks_register
+        base._callbacks_register = []
+      end
+
+      def self.setup(base)
+        base._callbacks_register.each do |item|
+          base.send(*item)
+        end
+      end
+
+      def define_callbacks(*args)
+        self._callbacks_register << [:define_callbacks, *args]
+      end
+
+      def define_model_callbacks(*args)
+        self._callbacks_register << [:define_model_callbacks, *args]
+      end
+    end
+
     extend ActiveSupport::Concern
 
     CALLBACKS = [
@@ -242,8 +266,11 @@ module ActiveRecord
       :before_destroy, :around_destroy, :after_destroy, :after_commit, :after_rollback
     ]
 
+    module ClassMethods
+      include ActiveModel::Callbacks
+    end
+
     included do
-      extend ActiveModel::Callbacks
       include ActiveModel::Validations::Callbacks
 
       define_model_callbacks :initialize, :find, :touch, :only => :after
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
index 20863e73aa..b8f99adc22 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
@@ -1,7 +1,7 @@
 require 'thread'
 require 'monitor'
 require 'set'
-require 'active_support/core_ext/module/synchronization'
+require 'active_support/core_ext/module/deprecation'
 
 module ActiveRecord
   # Raised when a connection could not be obtained within the connection
@@ -9,6 +9,13 @@ module ActiveRecord
   class ConnectionTimeoutError < ConnectionNotEstablished
   end
 
+  # Raised when a connection pool is full and another connection is requested
+  class PoolFullError < ConnectionNotEstablished
+    def initialize size, timeout
+      super("Connection pool of size #{size} and timeout #{timeout}s is full")
+    end
+  end
+
   module ConnectionAdapters
     # Connection pool base class for managing Active Record database
     # connections.
@@ -57,10 +64,35 @@ module ActiveRecord
     # * +wait_timeout+: number of seconds to block and wait for a connection
     #   before giving up and raising a timeout error (default 5 seconds).
     class ConnectionPool
-      attr_accessor :automatic_reconnect
-      attr_reader :spec, :connections
-      attr_reader :columns, :columns_hash, :primary_keys, :tables
-      attr_reader :column_defaults
+      # Every +frequency+ seconds, the reaper will call +reap+ on +pool+.
+      # A reaper instantiated with a nil frequency will never reap the
+      # connection pool.
+      #
+      # Configure the frequency by setting "reaping_frequency" in your
+      # database yaml file.
+      class Reaper
+        attr_reader :pool, :frequency
+
+        def initialize(pool, frequency)
+          @pool      = pool
+          @frequency = frequency
+        end
+
+        def run
+          return unless frequency
+          Thread.new(frequency, pool) { |t, p|
+            while true
+              sleep t
+              p.reap
+            end
+          }
+        end
+      end
+
+      include MonitorMixin
+
+      attr_accessor :automatic_reconnect, :timeout
+      attr_reader :spec, :connections, :size, :reaper
 
       # Creates a new ConnectionPool object. +spec+ is a ConnectionSpecification
       # object which describes database connection information (e.g. adapter,
@@ -69,88 +101,22 @@ module ActiveRecord
       #
       # The default ConnectionPool maximum size is 5.
       def initialize(spec)
+        super()
+
         @spec = spec
 
         # The cache of reserved connections mapped to threads
         @reserved_connections = {}
 
-        # The mutex used to synchronize pool access
-        @connection_mutex = Monitor.new
-        @queue = @connection_mutex.new_cond
         @timeout = spec.config[:wait_timeout] || 5
+        @reaper  = Reaper.new self, spec.config[:reaping_frequency]
+        @reaper.run
 
         # default max pool size to 5
         @size = (spec.config[:pool] && spec.config[:pool].to_i) || 5
 
         @connections         = []
-        @checked_out         = []
         @automatic_reconnect = true
-        @tables              = {}
-        @visitor             = nil
-
-        @columns     = Hash.new do |h, table_name|
-          h[table_name] = with_connection do |conn|
-
-            # Fetch a list of columns
-            conn.columns(table_name, "#{table_name} Columns").tap do |columns|
-
-              # set primary key information
-              columns.each do |column|
-                column.primary = column.name == primary_keys[table_name]
-              end
-            end
-          end
-        end
-
-        @columns_hash = Hash.new do |h, table_name|
-          h[table_name] = Hash[columns[table_name].map { |col|
-            [col.name, col]
-          }]
-        end
-
-        @column_defaults = Hash.new do |h, table_name|
-          h[table_name] = Hash[columns[table_name].map { |col|
-            [col.name, col.default]
-          }]
-        end
-
-        @primary_keys = Hash.new do |h, table_name|
-          h[table_name] = with_connection do |conn|
-            table_exists?(table_name) ? conn.primary_key(table_name) : 'id'
-          end
-        end
-      end
-
-      # A cached lookup for table existence.
-      def table_exists?(name)
-        return true if @tables.key? name
-
-        with_connection do |conn|
-          conn.tables.each { |table| @tables[table] = true }
-          @tables[name] = true if !@tables.key?(name) && conn.table_exists?(name)
-        end
-
-        @tables.key? name
-      end
-
-      # Clears out internal caches:
-      #
-      #   * columns
-      #   * columns_hash
-      #   * tables
-      def clear_cache!
-        @columns.clear
-        @columns_hash.clear
-        @column_defaults.clear
-        @tables.clear
-      end
-
-      # Clear out internal caches for table with +table_name+.
-      def clear_table_cache!(table_name)
-        @columns.delete table_name
-        @columns_hash.delete table_name
-        @column_defaults.delete table_name
-        @primary_keys.delete table_name
       end
 
       # Retrieve the connection associated with the current thread, or call
@@ -165,7 +131,7 @@ module ActiveRecord
       # Check to see if there is an active connection in this connection
       # pool.
       def active_connection?
-        @reserved_connections.key? current_connection_id
+        active_connections.any?
       end
 
       # Signal that the thread is finished with the current connection.
@@ -181,7 +147,7 @@ module ActiveRecord
       # connection when finished.
       def with_connection
         connection_id = current_connection_id
-        fresh_connection = true unless @reserved_connections[connection_id]
+        fresh_connection = true unless active_connection?
         yield connection
       ensure
         release_connection(connection_id) if fresh_connection
@@ -189,94 +155,80 @@ module ActiveRecord
 
       # Returns true if a connection has already been opened.
       def connected?
-        !@connections.empty?
+        synchronize { @connections.any? }
       end
 
       # Disconnects all connections in the pool, and clears the pool.
       def disconnect!
-        @reserved_connections.each do |name,conn|
-          checkin conn
-        end
-        @reserved_connections = {}
-        @connections.each do |conn|
-          conn.disconnect!
+        synchronize do
+          @reserved_connections = {}
+          @connections.each do |conn|
+            checkin conn
+            conn.disconnect!
+          end
+          @connections = []
         end
-        @connections = []
       end
 
       # Clears the cache which maps classes.
       def clear_reloadable_connections!
-        @reserved_connections.each do |name, conn|
-          checkin conn
-        end
-        @reserved_connections = {}
-        @connections.each do |conn|
-          conn.disconnect! if conn.requires_reloading?
-        end
-        @connections.delete_if do |conn|
-          conn.requires_reloading?
+        synchronize do
+          @reserved_connections = {}
+          @connections.each do |conn|
+            checkin conn
+            conn.disconnect! if conn.requires_reloading?
+          end
+          @connections.delete_if do |conn|
+            conn.requires_reloading?
+          end
         end
       end
 
       # Verify active connections and remove and disconnect connections
       # associated with stale threads.
       def verify_active_connections! #:nodoc:
-        clear_stale_cached_connections!
-        @connections.each do |connection|
-          connection.verify!
+        synchronize do
+          @connections.each do |connection|
+            connection.verify!
+          end
         end
       end
 
-      # Return any checked-out connections back to the pool by threads that
-      # are no longer alive.
-      def clear_stale_cached_connections!
-        keys = @reserved_connections.keys - Thread.list.find_all { |t|
-          t.alive?
-        }.map { |thread| thread.object_id }
-        keys.each do |key|
-          checkin @reserved_connections[key]
-          @reserved_connections.delete(key)
-        end
+      def clear_stale_cached_connections! # :nodoc:
       end
+      deprecate :clear_stale_cached_connections!
 
       # Check-out a database connection from the pool, indicating that you want
       # to use it. You should call #checkin when you no longer need this.
       #
-      # This is done by either returning an existing connection, or by creating
-      # a new connection. If the maximum number of connections for this pool has
-      # already been reached, but the pool is empty (i.e. they're all being used),
-      # then this method will wait until a thread has checked in a connection.
-      # The wait time is bounded however: if no connection can be checked out
-      # within the timeout specified for this pool, then a ConnectionTimeoutError
-      # exception will be raised.
+      # This is done by either returning and leasing existing connection, or by
+      # creating a new connection and leasing it.
+      #
+      # If all connections are leased and the pool is at capacity (meaning the
+      # number of currently leased connections is greater than or equal to the
+      # size limit set), an ActiveRecord::PoolFullError exception will be raised.
       #
       # Returns: an AbstractAdapter object.
       #
       # Raises:
-      # - ConnectionTimeoutError: no connection can be obtained from the pool
-      #   within the timeout period.
+      # - PoolFullError: no connection can be obtained from the pool.
       def checkout
         # Checkout an available connection
-        @connection_mutex.synchronize do
-          loop do
-            conn = if @checked_out.size < @connections.size
-                     checkout_existing_connection
-                   elsif @connections.size < @size
-                     checkout_new_connection
-                   end
-            return conn if conn
-
-            @queue.wait(@timeout)
-
-            if(@checked_out.size < @connections.size)
-              next
-            else
-              clear_stale_cached_connections!
-              if @size == @checked_out.size
-                raise ConnectionTimeoutError, "could not obtain a database connection#{" within #{@timeout} seconds" if @timeout}. The max pool size is currently #{@size}; consider increasing it."
-              end
-            end
+        synchronize do
+          # Try to find a connection that hasn't been leased, and lease it
+          conn = connections.find { |c| c.lease }
+
+          # If all connections were leased, and we have room to expand,
+          # create a new connection and lease it.
+          if !conn && connections.size < size
+            conn = checkout_new_connection
+            conn.lease
+          end
 
+          if conn
+            checkout_and_verify conn
+          else
+            raise PoolFullError.new(size, timeout)
           end
         end
       end
@@ -287,56 +239,69 @@ module ActiveRecord
       # +conn+: an AbstractAdapter object, which was obtained by earlier by
       # calling +checkout+ on this pool.
       def checkin(conn)
-        @connection_mutex.synchronize do
+        synchronize do
           conn.run_callbacks :checkin do
-            @checked_out.delete conn
-            @queue.signal
+            conn.expire
           end
         end
       end
 
-      synchronize :clear_reloadable_connections!, :verify_active_connections!,
-        :connected?, :disconnect!, :with => :@connection_mutex
+      # Remove a connection from the connection pool.  The connection will
+      # remain open and active but will no longer be managed by this pool.
+      def remove(conn)
+        synchronize do
+          @connections.delete conn
 
-      private
+          # FIXME: we might want to store the key on the connection so that removing
+          # from the reserved hash will be a little easier.
+          thread_id = @reserved_connections.keys.find { |k|
+            @reserved_connections[k] == conn
+          }
+          @reserved_connections.delete thread_id if thread_id
+        end
+      end
 
-      def new_connection
-        connection = ActiveRecord::Base.send(spec.adapter_method, spec.config)
+      # Removes dead connections from the pool.  A dead connection can occur
+      # if a programmer forgets to close a connection at the end of a thread
+      # or a thread dies unexpectedly.
+      def reap
+        synchronize do
+          stale = Time.now - @timeout
+          connections.dup.each do |conn|
+            remove conn if conn.in_use? && stale > conn.last_use && !conn.active?
+          end
+        end
+      end
 
-        # TODO: This is a bit icky, and in the long term we may want to change the method
-        #       signature for connections. Also, if we switch to have one visitor per
-        #       connection (and therefore per thread), we can get rid of the thread-local
-        #       variable in Arel::Visitors::ToSql.
-        @visitor ||= connection.class.visitor_for(self)
-        connection.visitor = @visitor
+      private
 
-        connection
+      def new_connection
+        ActiveRecord::Base.send(spec.adapter_method, spec.config)
       end
 
       def current_connection_id #:nodoc:
-        Thread.current.object_id
+        ActiveRecord::Base.connection_id ||= Thread.current.object_id
       end
 
       def checkout_new_connection
         raise ConnectionNotEstablished unless @automatic_reconnect
 
         c = new_connection
+        c.pool = self
         @connections << c
-        checkout_and_verify(c)
-      end
-
-      def checkout_existing_connection
-        c = (@connections - @checked_out).first
-        checkout_and_verify(c)
+        c
       end
 
       def checkout_and_verify(c)
         c.run_callbacks :checkout do
           c.verify!
-          @checked_out << c
         end
         c
       end
+
+      def active_connections
+        @connections.find_all { |c| c.in_use? }
+      end
     end
 
     # ConnectionHandler is a collection of ConnectionPool objects. It is used
@@ -367,10 +332,12 @@ module ActiveRecord
 
       def initialize(pools = {})
         @connection_pools = pools
+        @class_to_pool    = {}
       end
 
       def establish_connection(name, spec)
-        @connection_pools[name] = ConnectionAdapters::ConnectionPool.new(spec)
+        @connection_pools[spec] ||= ConnectionAdapters::ConnectionPool.new(spec)
+        @class_to_pool[name] = @connection_pools[spec]
       end
 
       # Returns true if there are any active connections among the connection
@@ -421,19 +388,20 @@ module ActiveRecord
       # can be used as an argument for establish_connection, for easily
       # re-establishing the connection.
       def remove_connection(klass)
-        pool = @connection_pools.delete(klass.name)
+        pool = @class_to_pool.delete(klass.name)
         return nil unless pool
 
+        @connection_pools.delete pool.spec
         pool.automatic_reconnect = false
         pool.disconnect!
         pool.spec.config
       end
 
       def retrieve_connection_pool(klass)
-        pool = @connection_pools[klass.name]
+        pool = @class_to_pool[klass.name]
         return pool if pool
-        return nil if ActiveRecord::Base == klass
-        retrieve_connection_pool klass.superclass
+        return nil if ActiveRecord::Model == klass
+        retrieve_connection_pool klass.active_record_super
       end
     end
 
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/connection_specification.rb b/activerecord/lib/active_record/connection_adapters/abstract/connection_specification.rb
deleted file mode 100644
index c08c0263b9..0000000000
--- a/activerecord/lib/active_record/connection_adapters/abstract/connection_specification.rb
+++ /dev/null
@@ -1,153 +0,0 @@
-module ActiveRecord
-  class Base
-    class ConnectionSpecification #:nodoc:
-      attr_reader :config, :adapter_method
-      def initialize (config, adapter_method)
-        @config, @adapter_method = config, adapter_method
-      end
-    end
-
-    ##
-    # :singleton-method:
-    # The connection handler
-    class_attribute :connection_handler, :instance_writer => false
-    self.connection_handler = ConnectionAdapters::ConnectionHandler.new
-
-    # Returns the connection currently associated with the class. This can
-    # also be used to "borrow" the connection to do database work that isn't
-    # easily done without going straight to SQL.
-    def connection
-      self.class.connection
-    end
-
-    # Establishes the connection to the database. Accepts a hash as input where
-    # the <tt>:adapter</tt> key must be specified with the name of a database adapter (in lower-case)
-    # example for regular databases (MySQL, Postgresql, etc):
-    #
-    #   ActiveRecord::Base.establish_connection(
-    #     :adapter  => "mysql",
-    #     :host     => "localhost",
-    #     :username => "myuser",
-    #     :password => "mypass",
-    #     :database => "somedatabase"
-    #   )
-    #
-    # Example for SQLite database:
-    #
-    #   ActiveRecord::Base.establish_connection(
-    #     :adapter => "sqlite",
-    #     :database  => "path/to/dbfile"
-    #   )
-    #
-    # Also accepts keys as strings (for parsing from YAML for example):
-    #
-    #   ActiveRecord::Base.establish_connection(
-    #     "adapter" => "sqlite",
-    #     "database"  => "path/to/dbfile"
-    #   )
-    #
-    # Or a URL:
-    #
-    #   ActiveRecord::Base.establish_connection(
-    #     "postgres://myuser:mypass@localhost/somedatabase"
-    #   )
-    #
-    # The exceptions AdapterNotSpecified, AdapterNotFound and ArgumentError
-    # may be returned on an error.
-    def self.establish_connection(spec = ENV["DATABASE_URL"])
-      case spec
-        when nil
-          raise AdapterNotSpecified unless defined?(Rails.env)
-          establish_connection(Rails.env)
-        when ConnectionSpecification
-          self.connection_handler.establish_connection(name, spec)
-        when Symbol, String
-          if configuration = configurations[spec.to_s]
-            establish_connection(configuration)
-          elsif spec.is_a?(String) && hash = connection_url_to_hash(spec)
-            establish_connection(hash)
-          else
-            raise AdapterNotSpecified, "#{spec} database is not configured"
-          end
-        else
-          spec = spec.symbolize_keys
-          unless spec.key?(:adapter) then raise AdapterNotSpecified, "database configuration does not specify adapter" end
-
-          begin
-            require "active_record/connection_adapters/#{spec[:adapter]}_adapter"
-          rescue LoadError => e
-            raise "Please install the #{spec[:adapter]} adapter: `gem install activerecord-#{spec[:adapter]}-adapter` (#{e})"
-          end
-
-          adapter_method = "#{spec[:adapter]}_connection"
-          unless respond_to?(adapter_method)
-            raise AdapterNotFound, "database configuration specifies nonexistent #{spec[:adapter]} adapter"
-          end
-
-          remove_connection
-          establish_connection(ConnectionSpecification.new(spec, adapter_method))
-      end
-    end
-
-    def self.connection_url_to_hash(url) # :nodoc:
-      config = URI.parse url
-      adapter = config.scheme
-      adapter = "postgresql" if adapter == "postgres"
-      spec = { :adapter  => adapter,
-               :username => config.user,
-               :password => config.password,
-               :port     => config.port,
-               :database => config.path.sub(%r{^/},""),
-               :host     => config.host }
-      spec.reject!{ |_,value| !value }
-      if config.query
-        options = Hash[config.query.split("&").map{ |pair| pair.split("=") }].symbolize_keys
-        spec.merge!(options)
-      end
-      spec
-    end
-
-    class << self
-      # Returns the connection currently associated with the class. This can
-      # also be used to "borrow" the connection to do database work unrelated
-      # to any of the specific Active Records.
-      def connection
-        retrieve_connection
-      end
-
-      # Returns the configuration of the associated connection as a hash:
-      #
-      #  ActiveRecord::Base.connection_config
-      #  # => {:pool=>5, :timeout=>5000, :database=>"db/development.sqlite3", :adapter=>"sqlite3"}
-      #
-      # Please use only for reading.
-      def connection_config
-        connection_pool.spec.config
-      end
-
-      def connection_pool
-        connection_handler.retrieve_connection_pool(self) or raise ConnectionNotEstablished
-      end
-
-      def retrieve_connection
-        connection_handler.retrieve_connection(self)
-      end
-
-      # Returns true if Active Record is connected.
-      def connected?
-        connection_handler.connected?(self)
-      end
-
-      def remove_connection(klass = self)
-        connection_handler.remove_connection(klass)
-      end
-
-      def clear_active_connections!
-        connection_handler.clear_active_connections!
-      end
-
-      delegate :clear_reloadable_connections!,
-        :clear_all_connections!,:verify_active_connections!, :to => :connection_handler
-    end
-  end
-end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
index dc4a53034b..eb8cff9610 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
@@ -130,7 +130,7 @@ module ActiveRecord
       #
       # In order to get around this problem, #transaction will emulate the effect
       # of nested transactions, by using savepoints:
-      # http://dev.mysql.com/doc/refman/5.0/en/savepoints.html
+      # http://dev.mysql.com/doc/refman/5.0/en/savepoint.html
       # Savepoints are supported by MySQL and PostgreSQL, but not SQLite3.
       #
       # It is safe to call this method if a database transaction is already open,
@@ -341,7 +341,7 @@ module ActiveRecord
 
         # Send a rollback message to all records after they have been rolled back. If rollback
         # is false, only rollback records since the last save point.
-        def rollback_transaction_records(rollback) #:nodoc
+        def rollback_transaction_records(rollback)
           if rollback
             records = @_current_transaction_records.flatten
             @_current_transaction_records.clear
@@ -361,7 +361,7 @@ module ActiveRecord
         end
 
         # Send a commit message to all records after they have been committed.
-        def commit_transaction_records #:nodoc
+        def commit_transaction_records
           records = @_current_transaction_records.flatten
           @_current_transaction_records.clear
           unless records.blank?
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
index 82f564e41d..132ca10f79 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
@@ -6,7 +6,7 @@ require 'bigdecimal/util'
 
 module ActiveRecord
   module ConnectionAdapters #:nodoc:
-    class IndexDefinition < Struct.new(:table, :name, :unique, :columns, :lengths) #:nodoc:
+    class IndexDefinition < Struct.new(:table, :name, :unique, :columns, :lengths, :orders) #:nodoc:
     end
 
     # Abstract representation of a column definition. Instances of this type
@@ -46,13 +46,13 @@ module ActiveRecord
     # +change_table+ is actually of this type:
     #
     #   class SomeMigration < ActiveRecord::Migration
-    #     def self.up
+    #     def up
     #       create_table :foo do |t|
     #         puts t.class  # => "ActiveRecord::ConnectionAdapters::TableDefinition"
     #       end
     #     end
     #
-    #     def self.down
+    #     def down
     #       ...
     #     end
     #   end
@@ -66,6 +66,7 @@ module ActiveRecord
 
       def initialize(base)
         @columns = []
+        @columns_hash = {}
         @base = base
       end
 
@@ -86,7 +87,7 @@ module ActiveRecord
 
       # Returns a ColumnDefinition for the column with name +name+.
       def [](name)
-        @columns.find {|column| column.name.to_s == name.to_s}
+        @columns_hash[name.to_s]
       end
 
       # Instantiates a new column for the table.
@@ -224,35 +225,38 @@ module ActiveRecord
       #     t.references :taggable, :polymorphic => { :default => 'Photo' }
       #   end
       def column(name, type, options = {})
-        column = self[name] || ColumnDefinition.new(@base, name, type)
-        if options[:limit]
-          column.limit = options[:limit]
-        elsif native[type.to_sym].is_a?(Hash)
-          column.limit = native[type.to_sym][:limit]
+        name = name.to_s
+        type = type.to_sym
+
+        column = self[name] || new_column_definition(@base, name, type)
+
+        limit = options.fetch(:limit) do
+          native[type][:limit] if native[type].is_a?(Hash)
         end
+
+        column.limit     = limit
         column.precision = options[:precision]
-        column.scale = options[:scale]
-        column.default = options[:default]
-        column.null = options[:null]
-        @columns << column unless @columns.include? column
+        column.scale     = options[:scale]
+        column.default   = options[:default]
+        column.null      = options[:null]
         self
       end
 
       %w( string text integer float decimal datetime timestamp time date binary boolean ).each do |column_type|
         class_eval <<-EOV, __FILE__, __LINE__ + 1
-          def #{column_type}(*args)                                               # def string(*args)
-            options = args.extract_options!                                       #   options = args.extract_options!
-            column_names = args                                                   #   column_names = args
-                                                                                  #
-            column_names.each { |name| column(name, '#{column_type}', options) }  #   column_names.each { |name| column(name, 'string', options) }
-          end                                                                     # end
+          def #{column_type}(*args)                                   # def string(*args)
+            options = args.extract_options!                           #   options = args.extract_options!
+            column_names = args                                       #   column_names = args
+            type = :'#{column_type}'                                  #   type = :string
+            column_names.each { |name| column(name, type, options) }  #   column_names.each { |name| column(name, type, options) }
+          end                                                         # end
         EOV
       end
 
       # Appends <tt>:datetime</tt> columns <tt>:created_at</tt> and
       # <tt>:updated_at</tt> to the table.
       def timestamps(*args)
-        options = args.extract_options!
+        options = { :null => false }.merge(args.extract_options!)
         column(:created_at, :datetime, options)
         column(:updated_at, :datetime, options)
       end
@@ -275,9 +279,16 @@ module ActiveRecord
       end
 
       private
-        def native
-          @base.native_database_types
-        end
+      def new_column_definition(base, name, type)
+        definition = ColumnDefinition.new base, name, type
+        @columns << definition
+        @columns_hash[name] = definition
+        definition
+      end
+
+      def native
+        @base.native_database_types
+      end
     end
 
     # Represents an SQL table in an abstract way for updating a table.
@@ -453,13 +464,13 @@ module ActiveRecord
           def #{column_type}(*args)                                          # def string(*args)
             options = args.extract_options!                                  #   options = args.extract_options!
             column_names = args                                              #   column_names = args
-                                                                             #
+            type = :'#{column_type}'                                         #   type = :string
             column_names.each do |name|                                      #   column_names.each do |name|
-              column = ColumnDefinition.new(@base, name, '#{column_type}')   #     column = ColumnDefinition.new(@base, name, 'string')
+              column = ColumnDefinition.new(@base, name.to_s, type)          #     column = ColumnDefinition.new(@base, name, type)
               if options[:limit]                                             #     if options[:limit]
                 column.limit = options[:limit]                               #       column.limit = options[:limit]
-              elsif native['#{column_type}'.to_sym].is_a?(Hash)              #     elsif native['string'.to_sym].is_a?(Hash)
-                column.limit = native['#{column_type}'.to_sym][:limit]       #       column.limit = native['string'.to_sym][:limit]
+              elsif native[type].is_a?(Hash)                                 #     elsif native[type].is_a?(Hash)
+                column.limit = native[type][:limit]                          #       column.limit = native[type][:limit]
               end                                                            #     end
               column.precision = options[:precision]                         #     column.precision = options[:precision]
               column.scale = options[:scale]                                 #     column.scale = options[:scale]
@@ -479,4 +490,3 @@ module ActiveRecord
 
   end
 end
-
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index 8e3ba1297e..20d3b4a1ef 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -1,4 +1,5 @@
 require 'active_support/core_ext/array/wrap'
+require 'active_support/deprecation/reporting'
 
 module ActiveRecord
   module ConnectionAdapters # :nodoc:
@@ -15,8 +16,6 @@ module ActiveRecord
         table_name[0...table_alias_length].gsub(/\./, '_')
       end
 
-      # def tables(name = nil) end
-
       # Checks to see if the table +table_name+ exists on the database.
       #
       # === Example
@@ -113,7 +112,7 @@ module ActiveRecord
       #   Defaults to +id+. If <tt>:id</tt> is false this option is ignored.
       #
       #   Also note that this just sets the primary key in the table. You additionally
-      #   need to configure the primary key in the model via the +set_primary_key+ macro.
+      #   need to configure the primary key in the model via +self.primary_key=+.
       #   Models do NOT auto-detect the primary key from their table definition.
       #
       # [<tt>:options</tt>]
@@ -302,15 +301,8 @@ module ActiveRecord
       # Adds a new index to the table. +column_name+ can be a single Symbol, or
       # an Array of Symbols.
       #
-      # The index will be named after the table and the first column name,
-      # unless you pass <tt>:name</tt> as an option.
-      #
-      # When creating an index on multiple columns, the first column is used as a name
-      # for the index. For example, when you specify an index on two columns
-      # [<tt>:first</tt>, <tt>:last</tt>], the DBMS creates an index for both columns as well as an
-      # index for the first column <tt>:first</tt>. Using just the first name for this index
-      # makes sense, because you will never have to create a singular index with this
-      # name.
+      # The index will be named after the table and the column name(s), unless
+      # you pass <tt>:name</tt> as an option.
       #
       # ===== Examples
       #
@@ -339,6 +331,14 @@ module ActiveRecord
       #  CREATE INDEX by_name_surname ON accounts(name(10), surname(15))
       #
       # Note: SQLite doesn't support index length
+      #
+      # ====== Creating an index with a sort order (desc or asc, asc is the default)
+      #  add_index(:accounts, [:branch_id, :party_id, :surname], :order => {:branch_id => :desc, :part_id => :asc})
+      # generates
+      #  CREATE INDEX by_branch_desc_party ON accounts(branch_id DESC, party_id ASC, surname)
+      #
+      # Note: mysql doesn't yet support index order (it accepts the syntax but ignores it)
+      #
       def add_index(table_name, column_name, options = {})
         index_name, index_type, index_columns = add_index_options(table_name, column_name, options)
         execute "CREATE #{index_type} INDEX #{quote_column_name(index_name)} ON #{quote_table_name(table_name)} (#{index_columns})"
@@ -405,7 +405,7 @@ module ActiveRecord
 
       def dump_schema_information #:nodoc:
         sm_table = ActiveRecord::Migrator.schema_migrations_table_name
-        migrated = select_values("SELECT version FROM #{sm_table}")
+        migrated = select_values("SELECT version FROM #{sm_table} ORDER BY version")
         migrated.map { |v| "INSERT INTO #{sm_table} (version) VALUES ('#{v}');" }.join("\n\n")
       end
 
@@ -426,6 +426,7 @@ module ActiveRecord
           si_table = Base.table_name_prefix + 'schema_info' + Base.table_name_suffix
 
           if table_exists?(si_table)
+            ActiveRecord::Deprecation.warn "Usage of the schema table `#{si_table}` is deprecated. Please switch to using `schema_migrations` table"
 
             old_version = select_value("SELECT version FROM #{quote_table_name(si_table)}").to_i
             assume_migrated_upto_version(old_version)
@@ -507,8 +508,8 @@ module ActiveRecord
       # ===== Examples
       #  add_timestamps(:suppliers)
       def add_timestamps(table_name)
-        add_column table_name, :created_at, :datetime
-        add_column table_name, :updated_at, :datetime
+        add_column table_name, :created_at, :datetime, :null => false
+        add_column table_name, :updated_at, :datetime, :null => false
       end
 
       # Removes the timestamp columns (created_at and updated_at) from the table definition.
@@ -520,9 +521,29 @@ module ActiveRecord
       end
 
       protected
+        def add_index_sort_order(option_strings, column_names, options = {})
+          if options.is_a?(Hash) && order = options[:order]
+            case order
+            when Hash
+              column_names.each {|name| option_strings[name] += " #{order[name].to_s.upcase}" if order.has_key?(name)}
+            when String
+              column_names.each {|name| option_strings[name] += " #{order.upcase}"}
+            end
+          end
+
+          return option_strings
+        end
+
         # Overridden by the mysql adapter for supporting index lengths
         def quoted_columns_for_index(column_names, options = {})
-          column_names.map {|name| quote_column_name(name) }
+          option_strings = Hash[column_names.map {|name| [name, '']}]
+
+          # add index sort order if supported
+          if supports_index_sort_order?
+            option_strings = add_index_sort_order(option_strings, column_names, options)
+          end
+
+          column_names.map {|name| quote_column_name(name) + option_strings[name]}
         end
 
         def options_include_default?(options)
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
index 443e61b527..edea414db7 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
@@ -3,12 +3,15 @@ require 'bigdecimal'
 require 'bigdecimal/util'
 require 'active_support/core_ext/benchmark'
 require 'active_support/deprecation'
+require 'active_record/connection_adapters/schema_cache'
+require 'monitor'
 
 module ActiveRecord
   module ConnectionAdapters # :nodoc:
     extend ActiveSupport::Autoload
 
     autoload :Column
+    autoload :ConnectionSpecification
 
     autoload_under 'abstract' do
       autoload :IndexDefinition,  'active_record/connection_adapters/abstract/schema_definitions'
@@ -24,7 +27,6 @@ module ActiveRecord
       autoload :ConnectionPool
       autoload :ConnectionHandler,       'active_record/connection_adapters/abstract/connection_pool'
       autoload :ConnectionManagement,    'active_record/connection_adapters/abstract/connection_pool'
-      autoload :ConnectionSpecification
 
       autoload :QueryCache
     end
@@ -47,39 +49,44 @@ module ActiveRecord
       include DatabaseLimits
       include QueryCache
       include ActiveSupport::Callbacks
+      include MonitorMixin
 
       define_callbacks :checkout, :checkin
 
-      attr_accessor :visitor
-
-      def initialize(connection, logger = nil) #:nodoc:
-        @active = nil
-        @connection, @logger = connection, logger
+      attr_accessor :visitor, :pool
+      attr_reader :schema_cache, :last_use, :in_use
+      alias :in_use? :in_use
+
+      def initialize(connection, logger = nil, pool = nil) #:nodoc:
+        super()
+
+        @active              = nil
+        @connection          = connection
+        @in_use              = false
+        @instrumenter        = ActiveSupport::Notifications.instrumenter
+        @last_use            = false
+        @logger              = logger
+        @open_transactions   = 0
+        @pool                = pool
+        @query_cache         = Hash.new { |h,sql| h[sql] = {} }
         @query_cache_enabled = false
-        @query_cache = Hash.new { |h,sql| h[sql] = {} }
-        @open_transactions = 0
-        @instrumenter = ActiveSupport::Notifications.instrumenter
-        @visitor = nil
-      end
-
-      # Returns a visitor instance for this adaptor, which conforms to the Arel::ToSql interface
-      def self.visitor_for(pool) # :nodoc:
-        adapter = pool.spec.config[:adapter]
-
-        if Arel::Visitors::VISITORS[adapter]
-          ActiveSupport::Deprecation.warn(
-            "Arel::Visitors::VISITORS is deprecated and will be removed. Database adapters " \
-            "should define a visitor_for method which returns the appropriate visitor for " \
-            "the database. For example, MysqlAdapter.visitor_for(pool) returns " \
-            "Arel::Visitors::MySQL.new(pool)."
-          )
-
-          Arel::Visitors::VISITORS[adapter].new(pool)
-        else
-          Arel::Visitors::ToSql.new(pool)
+        @schema_cache        = SchemaCache.new self
+        @visitor             = nil
+      end
+
+      def lease
+        synchronize do
+          unless in_use
+            @in_use   = true
+            @last_use = Time.now
+          end
         end
       end
 
+      def expire
+        @in_use = false
+      end
+
       # Returns the human-readable name of the adapter. Use mixed case - one
       # can always use downcase if needed.
       def adapter_name
@@ -130,6 +137,17 @@ module ActiveRecord
         false
       end
 
+      # Does this adapter support index sort order?
+      def supports_index_sort_order?
+        false
+      end
+
+      # Does this adapter support explain? As of this writing sqlite3,
+      # mysql2, and postgresql are the only ones that do.
+      def supports_explain?
+        false
+      end
+
       # QUOTING ==================================================
 
       # Override to return the quoted table name. Defaults to column quoting.
@@ -238,10 +256,19 @@ module ActiveRecord
         node
       end
 
+      def case_insensitive_comparison(table, attribute, column, value)
+        table[attribute].lower.eq(table.lower(value))
+      end
+
       def current_savepoint_name
         "active_record_#{open_transactions}"
       end
 
+      # Check the connection back in to the connection pool
+      def close
+        pool.checkin self
+      end
+
       protected
 
         def log(sql, name = "SQL", binds = [])
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index 4b7c74e0b8..560773ca86 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -4,6 +4,13 @@ module ActiveRecord
   module ConnectionAdapters
     class AbstractMysqlAdapter < AbstractAdapter
       class Column < ConnectionAdapters::Column # :nodoc:
+        attr_reader :collation
+
+        def initialize(name, default, sql_type = nil, null = true, collation = nil)
+          super(name, default, sql_type, null)
+          @collation = collation
+        end
+
         def extract_default(default)
           if sql_type =~ /blob/i || type == :text
             if default.blank?
@@ -28,6 +35,10 @@ module ActiveRecord
           raise NotImplementedError
         end
 
+        def case_sensitive?
+          collation && !collation.match(/_ci$/)
+        end
+
         private
 
         def simplified_type(field_type)
@@ -116,10 +127,7 @@ module ActiveRecord
         super(connection, logger)
         @connection_options, @config = connection_options, config
         @quoted_column_names, @quoted_table_names = {}, {}
-      end
-
-      def self.visitor_for(pool) # :nodoc:
-        Arel::Visitors::MySQL.new(pool)
+        @visitor = Arel::Visitors::MySQL.new self
       end
 
       def adapter_name #:nodoc:
@@ -144,6 +152,12 @@ module ActiveRecord
         true
       end
 
+      # Technically MySQL allows to create indexes with the sort order syntax
+      # but at the moment (5.5) it doesn't yet implement them
+      def supports_index_sort_order?
+        true
+      end
+
       def native_database_types
         NATIVE_DATABASE_TYPES
       end
@@ -157,8 +171,8 @@ module ActiveRecord
       end
 
       # Overridden by the adapters to instantiate their specific Column type.
-      def new_column(field, default, type, null) # :nodoc:
-        Column.new(field, default, type, null)
+      def new_column(field, default, type, null, collation) # :nodoc:
+        Column.new(field, default, type, null, collation)
       end
 
       # Must return the Mysql error number from the exception, if the exception has an
@@ -298,11 +312,11 @@ module ActiveRecord
           sql = "SHOW TABLES"
         end
 
-        select_all(sql).map do |table|
+        select_all(sql).map { |table|
           table.delete('Table_type')
           sql = "SHOW CREATE TABLE #{quote_table_name(table.to_a.first.last)}"
           exec_without_stmt(sql).first['Create Table'] + ";\n\n"
-        end.join("")
+        }.join
       end
 
       # Drops the database specified on the +name+ attribute
@@ -349,8 +363,10 @@ module ActiveRecord
         show_variable 'collation_database'
       end
 
-      def tables(name = nil, database = nil) #:nodoc:
-        sql = ["SHOW TABLES", database].compact.join(' IN ')
+      def tables(name = nil, database = nil, like = nil) #:nodoc:
+        sql = "SHOW TABLES "
+        sql << "IN #{database} " if database
+        sql << "LIKE #{quote(like)}" if like
 
         execute_and_free(sql, 'SCHEMA') do |result|
           result.collect { |field| field.first }
@@ -358,7 +374,8 @@ module ActiveRecord
       end
 
       def table_exists?(name)
-        return true if super
+        return false unless name
+        return true if tables(nil, nil, name).any?
 
         name          = name.to_s
         schema, table = name.split('.', 2)
@@ -368,7 +385,7 @@ module ActiveRecord
           schema = nil
         end
 
-        tables(nil, schema).include? table
+        tables(nil, schema, table).any?
       end
 
       # Returns an array of indexes for the given table.
@@ -393,10 +410,10 @@ module ActiveRecord
 
       # Returns an array of +Column+ objects for the table specified by +table_name+.
       def columns(table_name, name = nil)#:nodoc:
-        sql = "SHOW FIELDS FROM #{quote_table_name(table_name)}"
+        sql = "SHOW FULL FIELDS FROM #{quote_table_name(table_name)}"
         execute_and_free(sql, 'SCHEMA') do |result|
           each_hash(result).map do |field|
-            new_column(field[:Field], field[:Default], field[:Type], field[:Null] == "YES")
+            new_column(field[:Field], field[:Default], field[:Type], field[:Null] == "YES", field[:Collation])
           end
         end
       end
@@ -485,9 +502,14 @@ module ActiveRecord
 
       # Returns a table's primary key and belonging sequence.
       def pk_and_sequence_for(table)
-        execute_and_free("DESCRIBE #{quote_table_name(table)}", 'SCHEMA') do |result|
-          keys = each_hash(result).select { |row| row[:Key] == 'PRI' }.map { |row| row[:Field] }
-          keys.length == 1 ? [keys.first, nil] : nil
+        execute_and_free("SHOW CREATE TABLE #{quote_table_name(table)}", 'SCHEMA') do |result|
+          create_table = each_hash(result).first[:"Create Table"]
+          if create_table.to_s =~ /PRIMARY KEY\s+\((.+)\)/
+            keys = $1.split(",").map { |key| key.gsub(/`/, "") }
+            keys.length == 1 ? [keys.first, nil] : nil
+          else
+            nil
+          end
         end
       end
 
@@ -501,23 +523,43 @@ module ActiveRecord
         Arel::Nodes::Bin.new(node)
       end
 
+      def case_insensitive_comparison(table, attribute, column, value)
+        if column.case_sensitive?
+          super
+        else
+          table[attribute].eq(value)
+        end
+      end
+
       def limited_update_conditions(where_sql, quoted_table_name, quoted_primary_key)
         where_sql
       end
 
       protected
 
+      def add_index_length(option_strings, column_names, options = {})
+        if options.is_a?(Hash) && length = options[:length]
+          case length
+          when Hash
+            column_names.each {|name| option_strings[name] += "(#{length[name]})" if length.has_key?(name)}
+          when Fixnum
+            column_names.each {|name| option_strings[name] += "(#{length})"}
+          end
+        end
+
+        return option_strings
+      end
+
       def quoted_columns_for_index(column_names, options = {})
-        length = options[:length] if options.is_a?(Hash)
+        option_strings = Hash[column_names.map {|name| [name, '']}]
 
-        case length
-        when Hash
-          column_names.map {|name| length[name] ? "#{quote_column_name(name)}(#{length[name]})" : quote_column_name(name) }
-        when Fixnum
-          column_names.map {|name| "#{quote_column_name(name)}(#{length})"}
-        else
-          column_names.map {|name| quote_column_name(name) }
-        end
+        # add index length
+        option_strings = add_index_length(option_strings, column_names, options)
+
+        # add index sort order
+        option_strings = add_index_sort_order(option_strings, column_names, options)
+
+        column_names.map {|name| quote_column_name(name) + option_strings[name]}
       end
 
       def translate_exception(exception, message)
diff --git a/activerecord/lib/active_record/connection_adapters/column.rb b/activerecord/lib/active_record/connection_adapters/column.rb
index a7856539b7..6aa4a2c5b3 100644
--- a/activerecord/lib/active_record/connection_adapters/column.rb
+++ b/activerecord/lib/active_record/connection_adapters/column.rb
@@ -80,9 +80,10 @@ module ActiveRecord
         when :decimal              then klass.value_to_decimal(value)
         when :datetime, :timestamp then klass.string_to_time(value)
         when :time                 then klass.string_to_dummy_time(value)
-        when :date                 then klass.string_to_date(value)
+        when :date                 then klass.value_to_date(value)
         when :binary               then klass.binary_to_string(value)
         when :boolean              then klass.value_to_boolean(value)
+        when :hstore               then klass.cast_hstore(value)
         else value
         end
       end
@@ -97,9 +98,10 @@ module ActiveRecord
         when :decimal              then "#{klass}.value_to_decimal(#{var_name})"
         when :datetime, :timestamp then "#{klass}.string_to_time(#{var_name})"
         when :time                 then "#{klass}.string_to_dummy_time(#{var_name})"
-        when :date                 then "#{klass}.string_to_date(#{var_name})"
+        when :date                 then "#{klass}.value_to_date(#{var_name})"
         when :binary               then "#{klass}.binary_to_string(#{var_name})"
         when :boolean              then "#{klass}.value_to_boolean(#{var_name})"
+        when :hstore               then "#{klass}.cast_hstore(#{var_name})"
         else var_name
         end
       end
@@ -132,11 +134,15 @@ module ActiveRecord
           value
         end
 
-        def string_to_date(string)
-          return string unless string.is_a?(String)
-          return nil if string.empty?
-
-          fast_string_to_date(string) || fallback_string_to_date(string)
+        def value_to_date(value)
+          if value.is_a?(String)
+            return nil if value.empty?
+            fast_string_to_date(value) || fallback_string_to_date(value)
+          elsif value.respond_to?(:to_date)
+            value.to_date
+          else
+            value
+          end
         end
 
         def string_to_time(string)
diff --git a/activerecord/lib/active_record/connection_adapters/connection_specification.rb b/activerecord/lib/active_record/connection_adapters/connection_specification.rb
new file mode 100644
index 0000000000..8491d42b86
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/connection_specification.rb
@@ -0,0 +1,83 @@
+module ActiveRecord
+  module ConnectionAdapters
+    class ConnectionSpecification #:nodoc:
+      attr_reader :config, :adapter_method
+
+      def initialize(config, adapter_method)
+        @config, @adapter_method = config, adapter_method
+      end
+
+      def initialize_dup(original)
+        @config = original.config.dup
+      end
+
+      ##
+      # Builds a ConnectionSpecification from user input
+      class Resolver # :nodoc:
+        attr_reader :config, :klass, :configurations
+
+        def initialize(config, configurations)
+          @config         = config
+          @configurations = configurations
+        end
+
+        def spec
+          case config
+          when nil
+            raise AdapterNotSpecified unless defined?(Rails.env)
+            resolve_string_connection Rails.env
+          when Symbol, String
+            resolve_string_connection config.to_s
+          when Hash
+            resolve_hash_connection config
+          end
+        end
+
+        private
+        def resolve_string_connection(spec) # :nodoc:
+          hash = configurations.fetch(spec) do |k|
+            connection_url_to_hash(k)
+          end
+
+          raise(AdapterNotSpecified, "#{spec} database is not configured") unless hash
+
+          resolve_hash_connection hash
+        end
+
+        def resolve_hash_connection(spec) # :nodoc:
+          spec = spec.symbolize_keys
+
+          raise(AdapterNotSpecified, "database configuration does not specify adapter") unless spec.key?(:adapter)
+
+          begin
+            require "active_record/connection_adapters/#{spec[:adapter]}_adapter"
+          rescue LoadError => e
+            raise LoadError, "Please install the #{spec[:adapter]} adapter: `gem install activerecord-#{spec[:adapter]}-adapter` (#{e.message})", e.backtrace
+          end
+
+          adapter_method = "#{spec[:adapter]}_connection"
+
+          ConnectionSpecification.new(spec, adapter_method)
+        end
+
+        def connection_url_to_hash(url) # :nodoc:
+          config = URI.parse url
+          adapter = config.scheme
+          adapter = "postgresql" if adapter == "postgres"
+          spec = { :adapter  => adapter,
+                   :username => config.user,
+                   :password => config.password,
+                   :port     => config.port,
+                   :database => config.path.sub(%r{^/},""),
+                   :host     => config.host }
+          spec.reject!{ |_,value| !value }
+          if config.query
+            options = Hash[config.query.split("&").map{ |pair| pair.split("=") }].symbolize_keys
+            spec.merge!(options)
+          end
+          spec
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb
index 8b574518e5..6086c32dbe 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb
@@ -1,12 +1,12 @@
 require 'active_record/connection_adapters/abstract_mysql_adapter'
 
-gem 'mysql2', '~> 0.3.6'
+gem 'mysql2', '~> 0.3.10'
 require 'mysql2'
 
 module ActiveRecord
-  class Base
+  module ConnectionHandling
     # Establishes a connection to the database that's used by all Active Record objects.
-    def self.mysql2_connection(config)
+    def mysql2_connection(config)
       config[:username] = 'root' if config[:username].nil?
 
       if Mysql2::Client.const_defined? :FOUND_ROWS
@@ -35,6 +35,10 @@ module ActiveRecord
         configure_connection
       end
 
+      def supports_explain?
+        true
+      end
+
       # HELPER METHODS ===========================================
 
       def each_hash(result) # :nodoc:
@@ -47,8 +51,8 @@ module ActiveRecord
         end
       end
 
-      def new_column(field, default, type, null) # :nodoc:
-        Column.new(field, default, type, null)
+      def new_column(field, default, type, null, collation) # :nodoc:
+        Column.new(field, default, type, null, collation)
       end
 
       def error_number(exception)
@@ -93,6 +97,80 @@ module ActiveRecord
 
       # DATABASE STATEMENTS ======================================
 
+      def explain(arel, binds = [])
+        sql     = "EXPLAIN #{to_sql(arel)}"
+        start   = Time.now
+        result  = exec_query(sql, 'EXPLAIN', binds)
+        elapsed = Time.now - start
+
+        ExplainPrettyPrinter.new.pp(result, elapsed)
+      end
+
+      class ExplainPrettyPrinter # :nodoc:
+        # Pretty prints the result of a EXPLAIN in a way that resembles the output of the
+        # MySQL shell:
+        #
+        #   +----+-------------+-------+-------+---------------+---------+---------+-------+------+-------------+
+        #   | id | select_type | table | type  | possible_keys | key     | key_len | ref   | rows | Extra       |
+        #   +----+-------------+-------+-------+---------------+---------+---------+-------+------+-------------+
+        #   |  1 | SIMPLE      | users | const | PRIMARY       | PRIMARY | 4       | const |    1 |             |
+        #   |  1 | SIMPLE      | posts | ALL   | NULL          | NULL    | NULL    | NULL  |    1 | Using where |
+        #   +----+-------------+-------+-------+---------------+---------+---------+-------+------+-------------+
+        #   2 rows in set (0.00 sec)
+        #
+        # This is an exercise in Ruby hyperrealism :).
+        def pp(result, elapsed)
+          widths    = compute_column_widths(result)
+          separator = build_separator(widths)
+
+          pp = []
+
+          pp << separator
+          pp << build_cells(result.columns, widths)
+          pp << separator
+
+          result.rows.each do |row|
+            pp << build_cells(row, widths)
+          end
+
+          pp << separator
+          pp << build_footer(result.rows.length, elapsed)
+
+          pp.join("\n") + "\n"
+        end
+
+        private
+
+        def compute_column_widths(result)
+          [].tap do |widths|
+            result.columns.each_with_index do |column, i|
+              cells_in_column = [column] + result.rows.map {|r| r[i].nil? ? 'NULL' : r[i].to_s}
+              widths << cells_in_column.map(&:length).max
+            end
+          end
+        end
+
+        def build_separator(widths)
+          padding = 1
+          '+' + widths.map {|w| '-' * (w + (padding*2))}.join('+') + '+'
+        end
+
+        def build_cells(items, widths)
+          cells = []
+          items.each_with_index do |item, i|
+            item = 'NULL' if item.nil?
+            justifier = item.is_a?(Numeric) ? 'rjust' : 'ljust'
+            cells << item.to_s.send(justifier, widths[i])
+          end
+          '| ' + cells.join(' | ') + ' |'
+        end
+
+        def build_footer(nrows, elapsed)
+          rows_label = nrows == 1 ? 'row' : 'rows'
+          "#{nrows} #{rows_label} in set (%.2f sec)" % elapsed
+        end
+      end
+
       # FIXME: re-enable the following once a "better" query_cache solution is in core
       #
       # The overrides below perform much better than the originals in AbstractAdapter
diff --git a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
index a1824fe396..e432c5af32 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
@@ -18,9 +18,9 @@ class Mysql
 end
 
 module ActiveRecord
-  class Base
+  module ConnectionHandling
     # Establishes a connection to the database that's used by all Active Record objects.
-    def self.mysql_connection(config) # :nodoc:
+    def mysql_connection(config) # :nodoc:
       config = config.symbolize_keys
       host     = config[:host]
       port     = config[:port]
@@ -150,8 +150,8 @@ module ActiveRecord
         end
       end
 
-      def new_column(field, default, type, null) # :nodoc:
-        Column.new(field, default, type, null)
+      def new_column(field, default, type, null, collation) # :nodoc:
+        Column.new(field, default, type, null, collation)
       end
 
       def error_number(exception) # :nodoc:
@@ -224,52 +224,48 @@ module ActiveRecord
         @statements.clear
       end
 
-      if "<3".respond_to?(:encode)
-        # Taken from here:
-        #   https://github.com/tmtm/ruby-mysql/blob/master/lib/mysql/charset.rb
-        # Author: TOMITA Masahiro <tommy@tmtm.org>
-        ENCODINGS = {
-          "armscii8" => nil,
-          "ascii"    => Encoding::US_ASCII,
-          "big5"     => Encoding::Big5,
-          "binary"   => Encoding::ASCII_8BIT,
-          "cp1250"   => Encoding::Windows_1250,
-          "cp1251"   => Encoding::Windows_1251,
-          "cp1256"   => Encoding::Windows_1256,
-          "cp1257"   => Encoding::Windows_1257,
-          "cp850"    => Encoding::CP850,
-          "cp852"    => Encoding::CP852,
-          "cp866"    => Encoding::IBM866,
-          "cp932"    => Encoding::Windows_31J,
-          "dec8"     => nil,
-          "eucjpms"  => Encoding::EucJP_ms,
-          "euckr"    => Encoding::EUC_KR,
-          "gb2312"   => Encoding::EUC_CN,
-          "gbk"      => Encoding::GBK,
-          "geostd8"  => nil,
-          "greek"    => Encoding::ISO_8859_7,
-          "hebrew"   => Encoding::ISO_8859_8,
-          "hp8"      => nil,
-          "keybcs2"  => nil,
-          "koi8r"    => Encoding::KOI8_R,
-          "koi8u"    => Encoding::KOI8_U,
-          "latin1"   => Encoding::ISO_8859_1,
-          "latin2"   => Encoding::ISO_8859_2,
-          "latin5"   => Encoding::ISO_8859_9,
-          "latin7"   => Encoding::ISO_8859_13,
-          "macce"    => Encoding::MacCentEuro,
-          "macroman" => Encoding::MacRoman,
-          "sjis"     => Encoding::SHIFT_JIS,
-          "swe7"     => nil,
-          "tis620"   => Encoding::TIS_620,
-          "ucs2"     => Encoding::UTF_16BE,
-          "ujis"     => Encoding::EucJP_ms,
-          "utf8"     => Encoding::UTF_8,
-          "utf8mb4"  => Encoding::UTF_8,
-        }
-      else
-        ENCODINGS = Hash.new { |h,k| h[k] = k }
-      end
+      # Taken from here:
+      #   https://github.com/tmtm/ruby-mysql/blob/master/lib/mysql/charset.rb
+      # Author: TOMITA Masahiro <tommy@tmtm.org>
+      ENCODINGS = {
+        "armscii8" => nil,
+        "ascii"    => Encoding::US_ASCII,
+        "big5"     => Encoding::Big5,
+        "binary"   => Encoding::ASCII_8BIT,
+        "cp1250"   => Encoding::Windows_1250,
+        "cp1251"   => Encoding::Windows_1251,
+        "cp1256"   => Encoding::Windows_1256,
+        "cp1257"   => Encoding::Windows_1257,
+        "cp850"    => Encoding::CP850,
+        "cp852"    => Encoding::CP852,
+        "cp866"    => Encoding::IBM866,
+        "cp932"    => Encoding::Windows_31J,
+        "dec8"     => nil,
+        "eucjpms"  => Encoding::EucJP_ms,
+        "euckr"    => Encoding::EUC_KR,
+        "gb2312"   => Encoding::EUC_CN,
+        "gbk"      => Encoding::GBK,
+        "geostd8"  => nil,
+        "greek"    => Encoding::ISO_8859_7,
+        "hebrew"   => Encoding::ISO_8859_8,
+        "hp8"      => nil,
+        "keybcs2"  => nil,
+        "koi8r"    => Encoding::KOI8_R,
+        "koi8u"    => Encoding::KOI8_U,
+        "latin1"   => Encoding::ISO_8859_1,
+        "latin2"   => Encoding::ISO_8859_2,
+        "latin5"   => Encoding::ISO_8859_9,
+        "latin7"   => Encoding::ISO_8859_13,
+        "macce"    => Encoding::MacCentEuro,
+        "macroman" => Encoding::MacRoman,
+        "sjis"     => Encoding::SHIFT_JIS,
+        "swe7"     => nil,
+        "tis620"   => Encoding::TIS_620,
+        "ucs2"     => Encoding::UTF_16BE,
+        "ujis"     => Encoding::EucJP_ms,
+        "utf8"     => Encoding::UTF_8,
+        "utf8mb4"  => Encoding::UTF_8,
+      }
 
       # Get the client encoding for this database
       def client_encoding
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 5402918b1d..d2361b5378 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -7,9 +7,9 @@ gem 'pg', '~> 0.11'
 require 'pg'
 
 module ActiveRecord
-  class Base
+  module ConnectionHandling
     # Establishes a connection to the database that's used by all Active Record objects
-    def self.postgresql_connection(config) # :nodoc:
+    def postgresql_connection(config) # :nodoc:
       config = config.symbolize_keys
       host     = config[:host]
       port     = config[:port] || 5432
@@ -49,6 +49,42 @@ module ActiveRecord
             super
           end
         end
+
+        def cast_hstore(object)
+          if Hash === object
+            object.map { |k,v|
+              "#{escape_hstore(k)}=>#{escape_hstore(v)}"
+            }.join ', '
+          else
+            kvs = object.scan(/(?<!\\)".*?(?<!\\)"/).map { |o|
+              unescape_hstore(o[1...-1])
+            }
+            Hash[kvs.each_slice(2).to_a]
+          end
+        end
+
+        private
+        HSTORE_ESCAPE = {
+            ' '  => '\\ ',
+            '\\' => '\\\\',
+            '"'  => '\\"',
+            '='  => '\\=',
+        }
+        HSTORE_ESCAPE_RE   = Regexp.union(HSTORE_ESCAPE.keys)
+        HSTORE_UNESCAPE    = HSTORE_ESCAPE.invert
+        HSTORE_UNESCAPE_RE = Regexp.union(HSTORE_UNESCAPE.keys)
+
+        def unescape_hstore(value)
+          value.gsub(HSTORE_UNESCAPE_RE) do |match|
+            HSTORE_UNESCAPE[match]
+          end
+        end
+
+        def escape_hstore(value)
+          value.gsub(HSTORE_ESCAPE_RE) do |match|
+            HSTORE_ESCAPE[match]
+          end
+        end
       end
       # :startdoc:
 
@@ -79,53 +115,55 @@ module ActiveRecord
         # Maps PostgreSQL-specific data types to logical Rails types.
         def simplified_type(field_type)
           case field_type
-            # Numeric and monetary types
-            when /^(?:real|double precision)$/
-              :float
-            # Monetary types
-            when 'money'
-              :decimal
-            # Character types
-            when /^(?:character varying|bpchar)(?:\(\d+\))?$/
-              :string
-            # Binary data types
-            when 'bytea'
-              :binary
-            # Date/time types
-            when /^timestamp with(?:out)? time zone$/
-              :datetime
-            when 'interval'
-              :string
-            # Geometric types
-            when /^(?:point|line|lseg|box|"?path"?|polygon|circle)$/
-              :string
-            # Network address types
-            when /^(?:cidr|inet|macaddr)$/
-              :string
-            # Bit strings
-            when /^bit(?: varying)?(?:\(\d+\))?$/
-              :string
-            # XML type
-            when 'xml'
-              :xml
-            # tsvector type
-            when 'tsvector'
-              :tsvector
-            # Arrays
-            when /^\D+\[\]$/
-              :string
-            # Object identifier types
-            when 'oid'
-              :integer
-            # UUID type
-            when 'uuid'
-              :string
-            # Small and big integer types
-            when /^(?:small|big)int$/
-              :integer
-            # Pass through all types that are not specific to PostgreSQL.
-            else
-              super
+          # Numeric and monetary types
+          when /^(?:real|double precision)$/
+            :float
+          # Monetary types
+          when 'money'
+            :decimal
+          when 'hstore'
+            :hstore
+          # Character types
+          when /^(?:character varying|bpchar)(?:\(\d+\))?$/
+            :string
+          # Binary data types
+          when 'bytea'
+            :binary
+          # Date/time types
+          when /^timestamp with(?:out)? time zone$/
+            :datetime
+          when 'interval'
+            :string
+          # Geometric types
+          when /^(?:point|line|lseg|box|"?path"?|polygon|circle)$/
+            :string
+          # Network address types
+          when /^(?:cidr|inet|macaddr)$/
+            :string
+          # Bit strings
+          when /^bit(?: varying)?(?:\(\d+\))?$/
+            :string
+          # XML type
+          when 'xml'
+            :xml
+          # tsvector type
+          when 'tsvector'
+            :tsvector
+          # Arrays
+          when /^\D+\[\]$/
+            :string
+          # Object identifier types
+          when 'oid'
+            :integer
+          # UUID type
+          when 'uuid'
+            :string
+          # Small and big integer types
+          when /^(?:small|big)int$/
+            :integer
+          # Pass through all types that are not specific to PostgreSQL.
+          else
+            super
           end
         end
 
@@ -215,6 +253,10 @@ module ActiveRecord
           options = args.extract_options!
           column(args[0], 'tsvector', options)
         end
+
+        def hstore(name, options = {})
+          column(name, 'hstore', options)
+        end
       end
 
       ADAPTER_NAME = 'PostgreSQL'
@@ -247,6 +289,10 @@ module ActiveRecord
         true
       end
 
+      def supports_index_sort_order?
+        true
+      end
+
       class StatementPool < ConnectionAdapters::StatementPool
         def initialize(connection, max)
           super
@@ -278,13 +324,24 @@ module ActiveRecord
           cache.clear
         end
 
+        def delete(sql_key)
+          dealloc cache[sql_key]
+          cache.delete sql_key
+        end
+
         private
         def cache
           @cache[$$]
         end
 
         def dealloc(key)
-          @connection.query "DEALLOCATE #{key}"
+          @connection.query "DEALLOCATE #{key}" if connection_active?
+        end
+
+        def connection_active?
+          @connection.status == PGconn::CONNECTION_OK
+        rescue PGError
+          false
         end
       end
 
@@ -292,6 +349,7 @@ module ActiveRecord
       def initialize(connection, logger, connection_parameters, config)
         super(connection, logger)
         @connection_parameters, @config = connection_parameters, config
+        @visitor = Arel::Visitors::PostgreSQL.new self
 
         # @local_tz is initialized as nil to avoid warnings when connect tries to use it
         @local_tz = nil
@@ -308,10 +366,6 @@ module ActiveRecord
         @local_tz = execute('SHOW TIME ZONE', 'SCHEMA').first["TimeZone"]
       end
 
-      def self.visitor_for(pool) # :nodoc:
-        Arel::Visitors::PostgreSQL.new(pool)
-      end
-
       # Clears the prepared statements cache.
       def clear_cache!
         @statements.clear
@@ -378,6 +432,11 @@ module ActiveRecord
         true
       end
 
+      # Returns true.
+      def supports_explain?
+        true
+      end
+
       # Returns the configured supported identifier length supported by PostgreSQL
       def table_alias_length
         @table_alias_length ||= query('SHOW max_identifier_length')[0][0].to_i
@@ -502,6 +561,48 @@ module ActiveRecord
 
       # DATABASE STATEMENTS ======================================
 
+      def explain(arel, binds = [])
+        sql = "EXPLAIN #{to_sql(arel)}"
+        ExplainPrettyPrinter.new.pp(exec_query(sql, 'EXPLAIN', binds))
+      end
+
+      class ExplainPrettyPrinter # :nodoc:
+        # Pretty prints the result of a EXPLAIN in a way that resembles the output of the
+        # PostgreSQL shell:
+        #
+        #                                     QUERY PLAN
+        #   ------------------------------------------------------------------------------
+        #    Nested Loop Left Join  (cost=0.00..37.24 rows=8 width=0)
+        #      Join Filter: (posts.user_id = users.id)
+        #      ->  Index Scan using users_pkey on users  (cost=0.00..8.27 rows=1 width=4)
+        #            Index Cond: (id = 1)
+        #      ->  Seq Scan on posts  (cost=0.00..28.88 rows=8 width=4)
+        #            Filter: (posts.user_id = 1)
+        #   (6 rows)
+        #
+        def pp(result)
+          header = result.columns.first
+          lines  = result.rows.map(&:first)
+
+          # We add 2 because there's one char of padding at both sides, note
+          # the extra hyphens in the example above.
+          width = [header, *lines].map(&:length).max + 2
+
+          pp = []
+
+          pp << header.center(width).rstrip
+          pp << '-' * width
+
+          pp += lines.map {|line| " #{line}"}
+
+          nrows = result.rows.length
+          rows_label = nrows == 1 ? 'row' : 'rows'
+          pp << "(#{nrows} #{rows_label})"
+
+          pp.join("\n") + "\n"
+        end
+      end
+
       # Executes a SELECT query and returns an array of rows. Each row is an
       # array of field values.
       def select_rows(sql, name = nil)
@@ -743,16 +844,15 @@ module ActiveRecord
 
       # Returns an array of indexes for the given table.
       def indexes(table_name, name = nil)
-         schemas = schema_search_path.split(/,/).map { |p| quote(p) }.join(',')
          result = query(<<-SQL, name)
-           SELECT distinct i.relname, d.indisunique, d.indkey, t.oid
+           SELECT distinct i.relname, d.indisunique, d.indkey, pg_get_indexdef(d.indexrelid), t.oid
            FROM pg_class t
            INNER JOIN pg_index d ON t.oid = d.indrelid
            INNER JOIN pg_class i ON d.indexrelid = i.oid
            WHERE i.relkind = 'i'
              AND d.indisprimary = 'f'
              AND t.relname = '#{table_name}'
-             AND i.relnamespace IN (SELECT oid FROM pg_namespace WHERE nspname IN (#{schemas}) )
+             AND i.relnamespace IN (SELECT oid FROM pg_namespace WHERE nspname = ANY (current_schemas(false)) )
           ORDER BY i.relname
         SQL
 
@@ -761,7 +861,8 @@ module ActiveRecord
           index_name = row[0]
           unique = row[1] == 't'
           indkey = row[2].split(" ")
-          oid = row[3]
+          inddef = row[3]
+          oid = row[4]
 
           columns = Hash[query(<<-SQL, "Columns for index #{row[0]} on #{table_name}")]
           SELECT a.attnum, a.attname
@@ -771,7 +872,12 @@ module ActiveRecord
           SQL
 
           column_names = columns.values_at(*indkey).compact
-          column_names.empty? ? nil : IndexDefinition.new(table_name, index_name, unique, column_names)
+
+          # add info on sort order for columns (only desc order is explicitly specified, asc is the default)
+          desc_order_columns = inddef.scan(/(\w+) DESC/).flatten
+          orders = desc_order_columns.any? ? Hash[desc_order_columns.map {|order_column| [order_column, :desc]}] : {}
+
+          column_names.empty? ? nil : IndexDefinition.new(table_name, index_name, unique, column_names, [], orders)
         end.compact
       end
 
@@ -815,7 +921,7 @@ module ActiveRecord
 
       # Returns the active schema search path.
       def schema_search_path
-        @schema_search_path ||= query('SHOW search_path')[0][0]
+        @schema_search_path ||= query('SHOW search_path', 'SCHEMA')[0][0]
       end
 
       # Returns the current client message level.
@@ -911,12 +1017,14 @@ module ActiveRecord
       # Example:
       #   rename_table('octopuses', 'octopi')
       def rename_table(name, new_name)
+        clear_cache!
         execute "ALTER TABLE #{quote_table_name(name)} RENAME TO #{quote_table_name(new_name)}"
       end
 
       # Adds a new column to the named table.
       # See TableDefinition#column for details of the options you can use.
       def add_column(table_name, column_name, type, options = {})
+        clear_cache!
         add_column_sql = "ALTER TABLE #{quote_table_name(table_name)} ADD COLUMN #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
         add_column_options!(add_column_sql, options)
 
@@ -925,6 +1033,7 @@ module ActiveRecord
 
       # Changes the column of a table.
       def change_column(table_name, column_name, type, options = {})
+        clear_cache!
         quoted_table_name = quote_table_name(table_name)
 
         execute "ALTER TABLE #{quoted_table_name} ALTER COLUMN #{quote_column_name(column_name)} TYPE #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
@@ -935,10 +1044,12 @@ module ActiveRecord
 
       # Changes the default value of a table column.
       def change_column_default(table_name, column_name, default)
+        clear_cache!
         execute "ALTER TABLE #{quote_table_name(table_name)} ALTER COLUMN #{quote_column_name(column_name)} SET DEFAULT #{quote(default)}"
       end
 
       def change_column_null(table_name, column_name, null, default = nil)
+        clear_cache!
         unless null || default.nil?
           execute("UPDATE #{quote_table_name(table_name)} SET #{quote_column_name(column_name)}=#{quote(default)} WHERE #{quote_column_name(column_name)} IS NULL")
         end
@@ -947,6 +1058,7 @@ module ActiveRecord
 
       # Renames a column in a table.
       def rename_column(table_name, column_name, new_column_name)
+        clear_cache!
         execute "ALTER TABLE #{quote_table_name(table_name)} RENAME COLUMN #{quote_column_name(column_name)} TO #{quote_column_name(new_column_name)}"
       end
 
@@ -1030,26 +1142,54 @@ module ActiveRecord
         end
 
       private
+        FEATURE_NOT_SUPPORTED = "0A000" # :nodoc:
+
         def exec_no_cache(sql, binds)
           @connection.async_exec(sql)
         end
 
         def exec_cache(sql, binds)
-          unless @statements.key? sql
-            nextkey = @statements.next_key
-            @connection.prepare nextkey, sql
-            @statements[sql] = nextkey
+          begin
+            stmt_key = prepare_statement sql
+
+            # Clear the queue
+            @connection.get_last_result
+            @connection.send_query_prepared(stmt_key, binds.map { |col, val|
+              type_cast(val, col)
+            })
+            @connection.block
+            @connection.get_last_result
+          rescue PGError => e
+            # Get the PG code for the failure.  Annoyingly, the code for
+            # prepared statements whose return value may have changed is
+            # FEATURE_NOT_SUPPORTED.  Check here for more details:
+            # http://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/backend/utils/cache/plancache.c#l573
+            code = e.result.result_error_field(PGresult::PG_DIAG_SQLSTATE)
+            if FEATURE_NOT_SUPPORTED == code
+              @statements.delete sql_key(sql)
+              retry
+            else
+              raise e
+            end
           end
+        end
 
-          key = @statements[sql]
+        # Returns the statement identifier for the client side cache
+        # of statements
+        def sql_key(sql)
+          "#{schema_search_path}-#{sql}"
+        end
 
-          # Clear the queue
-          @connection.get_last_result
-          @connection.send_query_prepared(key, binds.map { |col, val|
-            type_cast(val, col)
-          })
-          @connection.block
-          @connection.get_last_result
+        # Prepare the statement if it hasn't been prepared, return
+        # the statement key.
+        def prepare_statement(sql)
+          sql_key = sql_key(sql)
+          unless @statements.key? sql_key
+            nextkey = @statements.next_key
+            @connection.prepare nextkey, sql
+            @statements[sql_key] = nextkey
+          end
+          @statements[sql_key]
         end
 
         # The internal PostgreSQL identifier of the money data type.
diff --git a/activerecord/lib/active_record/connection_adapters/schema_cache.rb b/activerecord/lib/active_record/connection_adapters/schema_cache.rb
new file mode 100644
index 0000000000..4e8932a695
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/schema_cache.rb
@@ -0,0 +1,50 @@
+module ActiveRecord
+  module ConnectionAdapters
+    class SchemaCache
+      attr_reader :columns, :columns_hash, :primary_keys, :tables
+      attr_reader :connection
+
+      def initialize(conn)
+        @connection = conn
+        @tables     = {}
+
+        @columns = Hash.new do |h, table_name|
+          h[table_name] = conn.columns(table_name, "#{table_name} Columns")
+        end
+
+        @columns_hash = Hash.new do |h, table_name|
+          h[table_name] = Hash[columns[table_name].map { |col|
+            [col.name, col]
+          }]
+        end
+
+        @primary_keys = Hash.new do |h, table_name|
+          h[table_name] = table_exists?(table_name) ? conn.primary_key(table_name) : nil
+        end
+      end
+
+      # A cached lookup for table existence.
+      def table_exists?(name)
+        return @tables[name] if @tables.key? name
+
+        @tables[name] = connection.table_exists?(name)
+      end
+
+      # Clears out internal caches
+      def clear!
+        @columns.clear
+        @columns_hash.clear
+        @primary_keys.clear
+        @tables.clear
+      end
+
+      # Clear out internal caches for table with +table_name+.
+      def clear_table_cache!(table_name)
+        @columns.delete table_name
+        @columns_hash.delete table_name
+        @primary_keys.delete table_name
+        @tables.delete table_name
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb b/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
index 0a0da0b5d3..ee5d10859c 100644
--- a/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
@@ -1,12 +1,12 @@
 require 'active_record/connection_adapters/sqlite_adapter'
 
-gem 'sqlite3', '~> 1.3.4'
+gem 'sqlite3', '~> 1.3.5'
 require 'sqlite3'
 
 module ActiveRecord
-  class Base
+  module ConnectionHandling
     # sqlite3 adapter reuses sqlite_connection.
-    def self.sqlite3_connection(config) # :nodoc:
+    def sqlite3_connection(config) # :nodoc:
       # Require database.
       unless config[:database]
         raise ArgumentError, "No database file specified. Missing argument: database"
@@ -47,11 +47,7 @@ module ActiveRecord
 
       # Returns the current database encoding format as a string, eg: 'UTF-8'
       def encoding
-        if @connection.respond_to?(:encoding)
-          @connection.encoding.to_s
-        else
-          @connection.execute('PRAGMA encoding')[0]['encoding']
-        end
+        @connection.encoding.to_s
       end
 
     end
diff --git a/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb b/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb
index 1932a849ee..69750a911d 100644
--- a/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb
@@ -16,7 +16,7 @@ module ActiveRecord
         end
 
         def binary_to_string(value)
-          if value.respond_to?(:force_encoding) && value.encoding != Encoding::ASCII_8BIT
+          if value.encoding != Encoding::ASCII_8BIT
             value = value.force_encoding(Encoding::ASCII_8BIT)
           end
 
@@ -89,10 +89,7 @@ module ActiveRecord
         @statements = StatementPool.new(@connection,
                                         config.fetch(:statement_limit) { 1000 })
         @config = config
-      end
-
-      def self.visitor_for(pool) # :nodoc:
-        Arel::Visitors::SQLite.new(pool)
+        @visitor = Arel::Visitors::SQLite.new self
       end
 
       def adapter_name #:nodoc:
@@ -125,6 +122,11 @@ module ActiveRecord
         true
       end
 
+      # Returns true.
+      def supports_explain?
+        true
+      end
+
       def requires_reloading?
         true
       end
@@ -157,6 +159,10 @@ module ActiveRecord
         sqlite_version >= '3.1.0'
       end
 
+      def supports_index_sort_order?
+        sqlite_version >= '3.3.0'
+      end
+
       def native_database_types #:nodoc:
         {
           :primary_key => default_primary_key_type,
@@ -195,29 +201,40 @@ module ActiveRecord
         end
       end
 
-      if "<3".encoding_aware?
-        def type_cast(value, column) # :nodoc:
-          return value.to_f if BigDecimal === value
-          return super unless String === value
-          return super unless column && value
-
-          value = super
-          if column.type == :string && value.encoding == Encoding::ASCII_8BIT
-            @logger.error "Binary data inserted for `string` type on column `#{column.name}`"
-            value.encode! 'utf-8'
-          end
-          value
-        end
-      else
-        def type_cast(value, column) # :nodoc:
-          return super unless BigDecimal === value
+      def type_cast(value, column) # :nodoc:
+        return value.to_f if BigDecimal === value
+        return super unless String === value
+        return super unless column && value
 
-          value.to_f
+        value = super
+        if column.type == :string && value.encoding == Encoding::ASCII_8BIT
+          @logger.error "Binary data inserted for `string` type on column `#{column.name}`"
+          value.encode! 'utf-8'
         end
+        value
       end
 
       # DATABASE STATEMENTS ======================================
 
+      def explain(arel, binds = [])
+        sql = "EXPLAIN QUERY PLAN #{to_sql(arel)}"
+        ExplainPrettyPrinter.new.pp(exec_query(sql, 'EXPLAIN', binds))
+      end
+
+      class ExplainPrettyPrinter
+        # Pretty prints the result of a EXPLAIN QUERY PLAN in a way that resembles
+        # the output of the SQLite shell:
+        #
+        #   0|0|0|SEARCH TABLE users USING INTEGER PRIMARY KEY (rowid=?) (~1 rows)
+        #   0|1|1|SCAN TABLE posts (~100000 rows)
+        #
+        def pp(result) # :nodoc:
+          result.rows.map do |row|
+            row.join('|')
+          end.join("\n") + "\n"
+        end
+      end
+
       def exec_query(sql, name = nil, binds = [])
         log(sql, name, binds) do
 
@@ -304,18 +321,23 @@ module ActiveRecord
 
       # SCHEMA STATEMENTS ========================================
 
-      def tables(name = 'SCHEMA') #:nodoc:
+      def tables(name = 'SCHEMA', table_name = nil) #:nodoc:
         sql = <<-SQL
           SELECT name
           FROM sqlite_master
           WHERE type = 'table' AND NOT name = 'sqlite_sequence'
         SQL
+        sql << " AND name = #{quote_table_name(table_name)}" if table_name
 
         exec_query(sql, name).map do |row|
           row['name']
         end
       end
 
+      def table_exists?(name)
+        name && tables('SCHEMA', name).any?
+      end
+
       # Returns an array of +SQLiteColumn+ objects for the table specified by +table_name+.
       def columns(table_name, name = nil) #:nodoc:
         table_structure(table_name).map do |field|
@@ -413,6 +435,8 @@ module ActiveRecord
             self.limit   = options[:limit] if options.include?(:limit)
             self.default = options[:default] if include_default
             self.null    = options[:null] if options.include?(:null)
+            self.precision = options[:precision] if options.include?(:precision)
+            self.scale   = options[:scale] if options.include?(:scale)
           end
         end
       end
@@ -467,6 +491,7 @@ module ActiveRecord
 
               @definition.column(column_name, column.type,
                 :limit => column.limit, :default => column.default,
+                :precision => column.precision, :scale => column.scale,
                 :null => column.null)
             end
             @definition.primary_key(primary_key(from)) if primary_key(from)
diff --git a/activerecord/lib/active_record/connection_handling.rb b/activerecord/lib/active_record/connection_handling.rb
new file mode 100644
index 0000000000..e9cd3d5e57
--- /dev/null
+++ b/activerecord/lib/active_record/connection_handling.rb
@@ -0,0 +1,100 @@
+require 'active_support/core_ext/module/delegation'
+
+module ActiveRecord
+  module ConnectionHandling
+    # Establishes the connection to the database. Accepts a hash as input where
+    # the <tt>:adapter</tt> key must be specified with the name of a database adapter (in lower-case)
+    # example for regular databases (MySQL, Postgresql, etc):
+    #
+    #   ActiveRecord::Base.establish_connection(
+    #     :adapter  => "mysql",
+    #     :host     => "localhost",
+    #     :username => "myuser",
+    #     :password => "mypass",
+    #     :database => "somedatabase"
+    #   )
+    #
+    # Example for SQLite database:
+    #
+    #   ActiveRecord::Base.establish_connection(
+    #     :adapter => "sqlite",
+    #     :database  => "path/to/dbfile"
+    #   )
+    #
+    # Also accepts keys as strings (for parsing from YAML for example):
+    #
+    #   ActiveRecord::Base.establish_connection(
+    #     "adapter" => "sqlite",
+    #     "database"  => "path/to/dbfile"
+    #   )
+    #
+    # Or a URL:
+    #
+    #   ActiveRecord::Base.establish_connection(
+    #     "postgres://myuser:mypass@localhost/somedatabase"
+    #   )
+    #
+    # The exceptions AdapterNotSpecified, AdapterNotFound and ArgumentError
+    # may be returned on an error.
+    def establish_connection(spec = ENV["DATABASE_URL"])
+      resolver = ConnectionAdapters::ConnectionSpecification::Resolver.new spec, configurations
+      spec = resolver.spec
+
+      unless respond_to?(spec.adapter_method)
+        raise AdapterNotFound, "database configuration specifies nonexistent #{spec.config[:adapter]} adapter"
+      end
+
+      remove_connection
+      connection_handler.establish_connection name, spec
+    end
+
+    # Returns the connection currently associated with the class. This can
+    # also be used to "borrow" the connection to do database work unrelated
+    # to any of the specific Active Records.
+    def connection
+      retrieve_connection
+    end
+
+    def connection_id
+      Thread.current['ActiveRecord::Base.connection_id']
+    end
+
+    def connection_id=(connection_id)
+      Thread.current['ActiveRecord::Base.connection_id'] = connection_id
+    end
+
+    # Returns the configuration of the associated connection as a hash:
+    #
+    #  ActiveRecord::Base.connection_config
+    #  # => {:pool=>5, :timeout=>5000, :database=>"db/development.sqlite3", :adapter=>"sqlite3"}
+    #
+    # Please use only for reading.
+    def connection_config
+      connection_pool.spec.config
+    end
+
+    def connection_pool
+      connection_handler.retrieve_connection_pool(self) or raise ConnectionNotEstablished
+    end
+
+    def retrieve_connection
+      connection_handler.retrieve_connection(self)
+    end
+
+    # Returns true if Active Record is connected.
+    def connected?
+      connection_handler.connected?(self)
+    end
+
+    def remove_connection(klass = self)
+      connection_handler.remove_connection(klass)
+    end
+
+    def clear_active_connections!
+      connection_handler.clear_active_connections!
+    end
+
+    delegate :clear_reloadable_connections!,
+      :clear_all_connections!,:verify_active_connections!, :to => :connection_handler
+  end
+end
diff --git a/activerecord/lib/active_record/core.rb b/activerecord/lib/active_record/core.rb
new file mode 100644
index 0000000000..980f8fe50f
--- /dev/null
+++ b/activerecord/lib/active_record/core.rb
@@ -0,0 +1,354 @@
+require 'active_support/concern'
+
+module ActiveRecord
+  module Core
+    extend ActiveSupport::Concern
+
+    included do
+      ##
+      # :singleton-method:
+      # Accepts a logger conforming to the interface of Log4r or the default Ruby 1.8+ Logger class,
+      # which is then passed on to any new database connections made and which can be retrieved on both
+      # a class and instance level by calling +logger+.
+      config_attribute :logger, :global => true
+
+      ##
+      # :singleton-method:
+      # Contains the database configuration - as is typically stored in config/database.yml -
+      # as a Hash.
+      #
+      # For example, the following database.yml...
+      #
+      #   development:
+      #     adapter: sqlite3
+      #     database: db/development.sqlite3
+      #
+      #   production:
+      #     adapter: sqlite3
+      #     database: db/production.sqlite3
+      #
+      # ...would result in ActiveRecord::Base.configurations to look like this:
+      #
+      #   {
+      #      'development' => {
+      #         'adapter'  => 'sqlite3',
+      #         'database' => 'db/development.sqlite3'
+      #      },
+      #      'production' => {
+      #         'adapter'  => 'sqlite3',
+      #         'database' => 'db/production.sqlite3'
+      #      }
+      #   }
+      config_attribute :configurations, :global => true
+      self.configurations = {}
+
+      ##
+      # :singleton-method:
+      # Determines whether to use Time.local (using :local) or Time.utc (using :utc) when pulling
+      # dates and times from the database. This is set to :local by default.
+      config_attribute :default_timezone, :global => true
+      self.default_timezone = :local
+
+      ##
+      # :singleton-method:
+      # Specifies the format to use when dumping the database schema with Rails'
+      # Rakefile. If :sql, the schema is dumped as (potentially database-
+      # specific) SQL statements. If :ruby, the schema is dumped as an
+      # ActiveRecord::Schema file which can be loaded into any database that
+      # supports migrations. Use :ruby if you want to have different database
+      # adapters for, e.g., your development and test environments.
+      config_attribute :schema_format, :global => true
+      self.schema_format = :ruby
+
+      ##
+      # :singleton-method:
+      # Specify whether or not to use timestamps for migration versions
+      config_attribute :timestamped_migrations, :global => true
+      self.timestamped_migrations = true
+
+      ##
+      # :singleton-method:
+      # The connection handler
+      config_attribute :connection_handler
+      self.connection_handler = ConnectionAdapters::ConnectionHandler.new
+    end
+
+    module ClassMethods
+      def inherited(child_class) #:nodoc:
+        child_class.initialize_generated_modules
+        super
+      end
+
+      def initialize_generated_modules
+        # force attribute methods to be higher in inheritance hierarchy than other generated methods
+        generated_attribute_methods
+        generated_feature_methods
+      end
+
+      def generated_feature_methods
+        @generated_feature_methods ||= begin
+          mod = const_set(:GeneratedFeatureMethods, Module.new)
+          include mod
+          mod
+        end
+      end
+
+      # Returns a string like 'Post(id:integer, title:string, body:text)'
+      def inspect
+        if self == Base
+          super
+        elsif abstract_class?
+          "#{super}(abstract)"
+        elsif table_exists?
+          attr_list = columns.map { |c| "#{c.name}: #{c.type}" } * ', '
+          "#{super}(#{attr_list})"
+        else
+          "#{super}(Table doesn't exist)"
+        end
+      end
+
+      # Overwrite the default class equality method to provide support for association proxies.
+      def ===(object)
+        object.is_a?(self)
+      end
+
+      def arel_table
+        @arel_table ||= Arel::Table.new(table_name, arel_engine)
+      end
+
+      def arel_engine
+        @arel_engine ||= connection_handler.connection_pools[name] ? self : active_record_super.arel_engine
+      end
+
+      private
+
+      def relation #:nodoc:
+        @relation ||= Relation.new(self, arel_table)
+
+        if finder_needs_type_condition?
+          @relation.where(type_condition).create_with(inheritance_column.to_sym => sti_name)
+        else
+          @relation
+        end
+      end
+    end
+
+    # New objects can be instantiated as either empty (pass no construction parameter) or pre-set with
+    # attributes but not yet saved (pass a hash with key names matching the associated table column names).
+    # In both instances, valid attribute keys are determined by the column names of the associated table --
+    # hence you can't have attributes that aren't part of the table columns.
+    #
+    # +initialize+ respects mass-assignment security and accepts either +:as+ or +:without_protection+ options
+    # in the +options+ parameter.
+    #
+    # ==== Examples
+    #   # Instantiates a single new object
+    #   User.new(:first_name => 'Jamie')
+    #
+    #   # Instantiates a single new object using the :admin mass-assignment security role
+    #   User.new({ :first_name => 'Jamie', :is_admin => true }, :as => :admin)
+    #
+    #   # Instantiates a single new object bypassing mass-assignment security
+    #   User.new({ :first_name => 'Jamie', :is_admin => true }, :without_protection => true)
+    def initialize(attributes = nil, options = {})
+      @attributes = self.class.initialize_attributes(self.class.column_defaults.dup)
+      @association_cache = {}
+      @aggregation_cache = {}
+      @attributes_cache = {}
+      @new_record = true
+      @readonly = false
+      @destroyed = false
+      @marked_for_destruction = false
+      @previously_changed = {}
+      @changed_attributes = {}
+      @relation = nil
+
+      ensure_proper_type
+
+      populate_with_current_scope_attributes
+
+      assign_attributes(attributes, options) if attributes
+
+      yield self if block_given?
+      run_callbacks :initialize
+    end
+
+    # Initialize an empty model object from +coder+. +coder+ must contain
+    # the attributes necessary for initializing an empty model object. For
+    # example:
+    #
+    #   class Post < ActiveRecord::Base
+    #   end
+    #
+    #   post = Post.allocate
+    #   post.init_with('attributes' => { 'title' => 'hello world' })
+    #   post.title # => 'hello world'
+    def init_with(coder)
+      @attributes = self.class.initialize_attributes(coder['attributes'])
+      @relation = nil
+
+      @attributes_cache, @previously_changed, @changed_attributes = {}, {}, {}
+      @association_cache = {}
+      @aggregation_cache = {}
+      @readonly = @destroyed = @marked_for_destruction = false
+      @new_record = false
+      run_callbacks :find
+      run_callbacks :initialize
+
+      self
+    end
+
+    # Duped objects have no id assigned and are treated as new records. Note
+    # that this is a "shallow" copy as it copies the object's attributes
+    # only, not its associations. The extent of a "deep" copy is application
+    # specific and is therefore left to the application to implement according
+    # to its need.
+    # The dup method does not preserve the timestamps (created|updated)_(at|on).
+    def initialize_dup(other)
+      cloned_attributes = other.clone_attributes(:read_attribute_before_type_cast)
+      cloned_attributes.delete(self.class.primary_key)
+
+      @attributes = cloned_attributes
+
+      _run_after_initialize_callbacks if respond_to?(:_run_after_initialize_callbacks)
+
+      @changed_attributes = {}
+      self.class.column_defaults.each do |attr, orig_value|
+        @changed_attributes[attr] = orig_value if field_changed?(attr, orig_value, @attributes[attr])
+      end
+
+      @aggregation_cache = {}
+      @association_cache = {}
+      @attributes_cache = {}
+      @new_record  = true
+
+      ensure_proper_type
+      populate_with_current_scope_attributes
+      super
+    end
+
+    # Populate +coder+ with attributes about this record that should be
+    # serialized. The structure of +coder+ defined in this method is
+    # guaranteed to match the structure of +coder+ passed to the +init_with+
+    # method.
+    #
+    # Example:
+    #
+    #   class Post < ActiveRecord::Base
+    #   end
+    #   coder = {}
+    #   Post.new.encode_with(coder)
+    #   coder # => { 'id' => nil, ... }
+    def encode_with(coder)
+      coder['attributes'] = attributes
+    end
+
+    # Returns true if +comparison_object+ is the same exact object, or +comparison_object+
+    # is of the same type and +self+ has an ID and it is equal to +comparison_object.id+.
+    #
+    # Note that new records are different from any other record by definition, unless the
+    # other record is the receiver itself. Besides, if you fetch existing records with
+    # +select+ and leave the ID out, you're on your own, this predicate will return false.
+    #
+    # Note also that destroying a record preserves its ID in the model instance, so deleted
+    # models are still comparable.
+    def ==(comparison_object)
+      super ||
+        comparison_object.instance_of?(self.class) &&
+        id.present? &&
+        comparison_object.id == id
+    end
+    alias :eql? :==
+
+    # Delegates to id in order to allow two records of the same type and id to work with something like:
+    #   [ Person.find(1), Person.find(2), Person.find(3) ] & [ Person.find(1), Person.find(4) ] # => [ Person.find(1) ]
+    def hash
+      id.hash
+    end
+
+    # Freeze the attributes hash such that associations are still accessible, even on destroyed records.
+    def freeze
+      @attributes.freeze; self
+    end
+
+    # Returns +true+ if the attributes hash has been frozen.
+    def frozen?
+      @attributes.frozen?
+    end
+
+    # Allows sort on objects
+    def <=>(other_object)
+      if other_object.is_a?(self.class)
+        self.to_key <=> other_object.to_key
+      else
+        nil
+      end
+    end
+
+    # Returns +true+ if the record is read only. Records loaded through joins with piggy-back
+    # attributes will be marked as read only since they cannot be saved.
+    def readonly?
+      @readonly
+    end
+
+    # Marks this record as read only.
+    def readonly!
+      @readonly = true
+    end
+
+    # Returns the connection currently associated with the class. This can
+    # also be used to "borrow" the connection to do database work that isn't
+    # easily done without going straight to SQL.
+    def connection
+      self.class.connection
+    end
+
+    # Returns the contents of the record as a nicely formatted string.
+    def inspect
+      inspection = if @attributes
+                     self.class.column_names.collect { |name|
+                       if has_attribute?(name)
+                         "#{name}: #{attribute_for_inspect(name)}"
+                       end
+                     }.compact.join(", ")
+                   else
+                     "not initialized"
+                   end
+      "#<#{self.class} #{inspection}>"
+    end
+
+    # Hackery to accomodate Syck. Remove for 4.0.
+    def to_yaml(opts = {}) #:nodoc:
+      if YAML.const_defined?(:ENGINE) && !YAML::ENGINE.syck?
+        super
+      else
+        coder = {}
+        encode_with(coder)
+        YAML.quick_emit(self, opts) do |out|
+          out.map(taguri, to_yaml_style) do |map|
+            coder.each { |k, v| map.add(k, v) }
+          end
+        end
+      end
+    end
+
+    # Hackery to accomodate Syck. Remove for 4.0.
+    def yaml_initialize(tag, coder) #:nodoc:
+      init_with(coder)
+    end
+
+    private
+
+    # Under Ruby 1.9, Array#flatten will call #to_ary (recursively) on each of the elements
+    # of the array, and then rescues from the possible NoMethodError. If those elements are
+    # ActiveRecord::Base's, then this triggers the various method_missing's that we have,
+    # which significantly impacts upon performance.
+    #
+    # So we can avoid the method_missing hit by explicitly defining #to_ary as nil here.
+    #
+    # See also http://tenderlovemaking.com/2011/06/28/til-its-ok-to-return-nil-from-to_ary/
+    def to_ary # :nodoc:
+      nil
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/counter_cache.rb b/activerecord/lib/active_record/counter_cache.rb
index 3c7defedac..031918712a 100644
--- a/activerecord/lib/active_record/counter_cache.rb
+++ b/activerecord/lib/active_record/counter_cache.rb
@@ -65,7 +65,7 @@ module ActiveRecord
     #   Post.update_counters [10, 15], :comment_count => 1
     #   # Executes the following SQL:
     #   # UPDATE posts
-    #   #    SET comment_count = COALESCE(comment_count, 0) + 1,
+    #   #    SET comment_count = COALESCE(comment_count, 0) + 1
     #   #  WHERE id IN (10, 15)
     def update_counters(id, counters)
       updates = counters.map do |counter_name, value|
diff --git a/activerecord/lib/active_record/dynamic_matchers.rb b/activerecord/lib/active_record/dynamic_matchers.rb
new file mode 100644
index 0000000000..e9068089f0
--- /dev/null
+++ b/activerecord/lib/active_record/dynamic_matchers.rb
@@ -0,0 +1,79 @@
+module ActiveRecord
+  module DynamicMatchers
+    def respond_to?(method_id, include_private = false)
+      if match = DynamicFinderMatch.match(method_id)
+        return true if all_attributes_exists?(match.attribute_names)
+      elsif match = DynamicScopeMatch.match(method_id)
+        return true if all_attributes_exists?(match.attribute_names)
+      end
+
+      super
+    end
+
+    private
+
+    # Enables dynamic finders like <tt>User.find_by_user_name(user_name)</tt> and
+    # <tt>User.scoped_by_user_name(user_name). Refer to Dynamic attribute-based finders
+    # section at the top of this file for more detailed information.
+    #
+    # It's even possible to use all the additional parameters to +find+. For example, the
+    # full interface for +find_all_by_amount+ is actually <tt>find_all_by_amount(amount, options)</tt>.
+    #
+    # Each dynamic finder using <tt>scoped_by_*</tt> is also defined in the class after it
+    # is first invoked, so that future attempts to use it do not run through method_missing.
+    def method_missing(method_id, *arguments, &block)
+      if match = (DynamicFinderMatch.match(method_id) || DynamicScopeMatch.match(method_id))
+        attribute_names = match.attribute_names
+        super unless all_attributes_exists?(attribute_names)
+        if arguments.size < attribute_names.size
+          method_trace = "#{__FILE__}:#{__LINE__}:in `#{method_id}'"
+          backtrace = [method_trace] + caller
+          raise ArgumentError, "wrong number of arguments (#{arguments.size} for #{attribute_names.size})", backtrace
+        end
+        if match.respond_to?(:scope?) && match.scope?
+          self.class_eval <<-METHOD, __FILE__, __LINE__ + 1
+            def self.#{method_id}(*args)                                    # def self.scoped_by_user_name_and_password(*args)
+              attributes = Hash[[:#{attribute_names.join(',:')}].zip(args)] #   attributes = Hash[[:user_name, :password].zip(args)]
+                                                                            #
+              scoped(:conditions => attributes)                             #   scoped(:conditions => attributes)
+            end                                                             # end
+          METHOD
+          send(method_id, *arguments)
+        elsif match.finder?
+          options = arguments.extract_options!
+          relation = options.any? ? scoped(options) : scoped
+          relation.send :find_by_attributes, match, attribute_names, *arguments, &block
+        elsif match.instantiator?
+          scoped.send :find_or_instantiator_by_attributes, match, attribute_names, *arguments, &block
+        end
+      else
+        super
+      end
+    end
+
+    # Similar in purpose to +expand_hash_conditions_for_aggregates+.
+    def expand_attribute_names_for_aggregates(attribute_names)
+      attribute_names.map { |attribute_name|
+        unless (aggregation = reflect_on_aggregation(attribute_name.to_sym)).nil?
+          aggregate_mapping(aggregation).map do |field_attr, _|
+            field_attr.to_sym
+          end
+        else
+          attribute_name.to_sym
+        end
+      }.flatten
+    end
+
+    def all_attributes_exists?(attribute_names)
+      (expand_attribute_names_for_aggregates(attribute_names) -
+       column_methods_hash.keys).empty?
+    end
+
+    def aggregate_mapping(reflection)
+      mapping = reflection.options[:mapping] || [reflection.name, reflection.name]
+      mapping.first.is_a?(Array) ? mapping : [mapping]
+    end
+
+
+  end
+end
diff --git a/activerecord/lib/active_record/errors.rb b/activerecord/lib/active_record/errors.rb
index 8262b60f6e..fc80f3081e 100644
--- a/activerecord/lib/active_record/errors.rb
+++ b/activerecord/lib/active_record/errors.rb
@@ -99,6 +99,16 @@ module ActiveRecord
   #
   # Read more about optimistic locking in ActiveRecord::Locking module RDoc.
   class StaleObjectError < ActiveRecordError
+    attr_reader :record, :attempted_action
+
+    def initialize(record, attempted_action)
+      @record = record
+      @attempted_action = attempted_action
+    end
+
+    def message
+      "Attempted to #{attempted_action} a stale object: #{record.class.name}"
+    end
   end
 
   # Raised when association is being configured improperly or
@@ -170,8 +180,7 @@ module ActiveRecord
     end
   end
 
-  # Raised when a model attempts to fetch its primary key from the database, but the table
-  # has no primary key declared.
+  # Raised when a primary key is needed, but there is not one specified in the schema or model.
   class UnknownPrimaryKey < ActiveRecordError
     attr_reader :model
 
diff --git a/activerecord/lib/active_record/explain.rb b/activerecord/lib/active_record/explain.rb
new file mode 100644
index 0000000000..e502d7e52b
--- /dev/null
+++ b/activerecord/lib/active_record/explain.rb
@@ -0,0 +1,80 @@
+require 'active_support/core_ext/class/attribute'
+
+module ActiveRecord
+  module Explain
+    def self.extended(base)
+      # If a query takes longer than these many seconds we log its query plan
+      # automatically. nil disables this feature.
+      base.config_attribute :auto_explain_threshold_in_seconds, :global => true
+    end
+
+    # If auto explain is enabled, this method triggers EXPLAIN logging for the
+    # queries triggered by the block if it takes more than the threshold as a
+    # whole. That is, the threshold is not checked against each individual
+    # query, but against the duration of the entire block. This approach is
+    # convenient for relations.
+    #
+    # The available_queries_for_explain thread variable collects the queries
+    # to be explained. If the value is nil, it means queries are not being
+    # currently collected. A false value indicates collecting is turned
+    # off. Otherwise it is an array of queries.
+    def logging_query_plan # :nodoc:
+      threshold = auto_explain_threshold_in_seconds
+      current   = Thread.current
+      if threshold && current[:available_queries_for_explain].nil?
+        begin
+          queries = current[:available_queries_for_explain] = []
+          start = Time.now
+          result = yield
+          logger.warn(exec_explain(queries)) if Time.now - start > threshold
+          result
+        ensure
+          current[:available_queries_for_explain] = nil
+        end
+      else
+        yield
+      end
+    end
+
+    # Relation#explain needs to be able to collect the queries regardless of
+    # whether auto explain is enabled. This method serves that purpose.
+    def collecting_queries_for_explain # :nodoc:
+      current = Thread.current
+      original, current[:available_queries_for_explain] = current[:available_queries_for_explain], []
+      return yield, current[:available_queries_for_explain]
+    ensure
+      # Note that the return value above does not depend on this assigment.
+      current[:available_queries_for_explain] = original
+    end
+
+    # Makes the adapter execute EXPLAIN for the tuples of queries and bindings.
+    # Returns a formatted string ready to be logged.
+    def exec_explain(queries) # :nodoc:
+      queries && queries.map do |sql, bind|
+        [].tap do |msg|
+          msg << "EXPLAIN for: #{sql}"
+          unless bind.empty?
+            bind_msg = bind.map {|col, val| [col.name, val]}.inspect
+            msg.last << " #{bind_msg}"
+          end
+          msg << connection.explain(sql, bind)
+        end.join("\n")
+      end.join("\n")
+    end
+
+    # Silences automatic EXPLAIN logging for the duration of the block.
+    #
+    # This has high priority, no EXPLAINs will be run even if downwards
+    # the threshold is set to 0.
+    #
+    # As the name of the method suggests this only applies to automatic
+    # EXPLAINs, manual calls to +ActiveRecord::Relation#explain+ run.
+    def silence_auto_explain
+      current = Thread.current
+      original, current[:available_queries_for_explain] = current[:available_queries_for_explain], false
+      yield
+    ensure
+      current[:available_queries_for_explain] = original
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/explain_subscriber.rb b/activerecord/lib/active_record/explain_subscriber.rb
new file mode 100644
index 0000000000..fc76410499
--- /dev/null
+++ b/activerecord/lib/active_record/explain_subscriber.rb
@@ -0,0 +1,21 @@
+require 'active_support/notifications'
+
+module ActiveRecord
+  class ExplainSubscriber # :nodoc:
+    def call(*args)
+      if queries = Thread.current[:available_queries_for_explain]
+        payload = args.last
+        queries << payload.values_at(:sql, :binds) unless ignore_payload?(payload)
+      end
+    end
+
+    # SCHEMA queries cannot be EXPLAINed, also we do not want to run EXPLAIN on
+    # our own EXPLAINs now matter how loopingly beautiful that would be.
+    IGNORED_PAYLOADS = %w(SCHEMA EXPLAIN)
+    def ignore_payload?(payload)
+      payload[:exception] || IGNORED_PAYLOADS.include?(payload[:name])
+    end
+
+    ActiveSupport::Notifications.subscribe("sql.active_record", new)
+  end
+end
diff --git a/activerecord/lib/active_record/fixtures.rb b/activerecord/lib/active_record/fixtures.rb
index 97af15c9e8..c59c00f424 100644
--- a/activerecord/lib/active_record/fixtures.rb
+++ b/activerecord/lib/active_record/fixtures.rb
@@ -10,7 +10,6 @@ require 'zlib'
 require 'active_support/dependencies'
 require 'active_support/core_ext/array/wrap'
 require 'active_support/core_ext/object/blank'
-require 'active_support/core_ext/logger'
 require 'active_support/ordered_hash'
 require 'active_record/fixtures/file'
 
@@ -22,8 +21,6 @@ else
   end
 end
 
-class FixturesFileNotFound < StandardError; end
-
 module ActiveRecord
   # \Fixtures are a way of organizing data that you want to test against; in short, sample data.
   #
@@ -391,10 +388,15 @@ module ActiveRecord
 
     @@all_cached_fixtures = Hash.new { |h,k| h[k] = {} }
 
-    def self.find_table_name(table_name) # :nodoc:
+    def self.default_fixture_model_name(fixture_name) # :nodoc:
       ActiveRecord::Base.pluralize_table_names ?
-        table_name.to_s.singularize.camelize :
-        table_name.to_s.camelize
+        fixture_name.singularize.camelize :
+        fixture_name.camelize
+    end
+
+    def self.default_fixture_table_name(fixture_name) # :nodoc:
+       "#{ActiveRecord::Base.table_name_prefix}"\
+         "#{fixture_name.tr('/', '_')}#{ActiveRecord::Base.table_name_suffix}".to_sym
     end
 
     def self.reset_cache
@@ -444,9 +446,6 @@ module ActiveRecord
 
     def self.create_fixtures(fixtures_directory, table_names, class_names = {})
       table_names = [table_names].flatten.map { |n| n.to_s }
-      table_names.each { |n|
-        class_names[n.tr('/', '_').to_sym] = n.classify if n.include?('/')
-      }
 
       # FIXME: Apparently JK uses this.
       connection = block_given? ? yield : ActiveRecord::Base.connection
@@ -460,12 +459,12 @@ module ActiveRecord
           fixtures_map = {}
 
           fixture_files = files_to_read.map do |path|
-            table_name = path.tr '/', '_'
+            fixture_name = path
 
-            fixtures_map[path] = ActiveRecord::Fixtures.new(
+            fixtures_map[fixture_name] = new( # ActiveRecord::Fixtures.new
               connection,
-              table_name,
-              class_names[table_name.to_sym] || table_name.classify,
+              fixture_name,
+              class_names[fixture_name] || default_fixture_model_name(fixture_name),
               ::File.join(fixtures_directory, path))
           end
 
@@ -489,8 +488,8 @@ module ActiveRecord
 
             # Cap primary key sequences to max(pk).
             if connection.respond_to?(:reset_pk_sequence!)
-              table_names.each do |table_name|
-                connection.reset_pk_sequence!(table_name.tr('/', '_'))
+              fixture_files.each do |ff|
+                connection.reset_pk_sequence!(ff.table_name)
               end
             end
           end
@@ -509,25 +508,27 @@ module ActiveRecord
 
     attr_reader :table_name, :name, :fixtures, :model_class
 
-    def initialize(connection, table_name, class_name, fixture_path)
+    def initialize(connection, fixture_name, class_name, fixture_path)
       @connection   = connection
-      @table_name   = table_name
       @fixture_path = fixture_path
-      @name         = table_name # preserve fixture base name
+      @name         = fixture_name
       @class_name   = class_name
 
       @fixtures     = ActiveSupport::OrderedHash.new
-      @table_name   = "#{ActiveRecord::Base.table_name_prefix}#{@table_name}#{ActiveRecord::Base.table_name_suffix}"
 
       # Should be an AR::Base type class
       if class_name.is_a?(Class)
-        @table_name   = class_name.table_name
-        @connection   = class_name.connection
-        @model_class  = class_name
+        @model_class = class_name
       else
-        @model_class  = class_name.constantize rescue nil
+        @model_class = class_name.constantize rescue nil
       end
 
+      @connection  = model_class.connection if model_class && model_class.respond_to?(:connection)
+
+      @table_name = ( model_class.respond_to?(:table_name) ?
+                      model_class.table_name :
+                      self.class.default_fixture_table_name(fixture_name) )
+
       read_fixture_files
     end
 
@@ -562,7 +563,7 @@ module ActiveRecord
       rows[table_name] = fixtures.map do |label, fixture|
         row = fixture.to_hash
 
-        if model_class && model_class < ActiveRecord::Base
+        if model_class && model_class < ActiveRecord::Model
           # fill in timestamp columns if they aren't specified and the model is set to record_timestamps
           if model_class.record_timestamps
             timestamp_column_names.each do |name|
@@ -622,7 +623,7 @@ module ActiveRecord
 
     private
       def primary_key_name
-        @primary_key_name ||= model_class && model_class.primary_key? && model_class.primary_key
+        @primary_key_name ||= model_class && model_class.primary_key
       end
 
       def has_primary_key_column?
@@ -644,14 +645,6 @@ module ActiveRecord
       end
 
       def read_fixture_files
-        if ::File.file?(yaml_file_path)
-          read_yaml_fixture_files
-        else
-          raise FixturesFileNotFound, "Could not find #{yaml_file_path}"
-        end
-      end
-
-      def read_yaml_fixture_files
         yaml_files = Dir["#{@fixture_path}/**/*.yml"].select { |f|
           ::File.file?(f)
         } + [yaml_file_path]
@@ -734,14 +727,29 @@ module ActiveRecord
       self.use_instantiated_fixtures = false
       self.pre_loaded_fixtures = false
 
-      self.fixture_class_names = Hash.new do |h, table_name|
-        h[table_name] = ActiveRecord::Fixtures.find_table_name(table_name)
+      self.fixture_class_names = Hash.new do |h, fixture_name|
+        h[fixture_name] = ActiveRecord::Fixtures.default_fixture_model_name(fixture_name)
       end
     end
 
     module ClassMethods
+      # Sets the model class for a fixture when the class name cannot be inferred from the fixture name.
+      #
+      # Examples:
+      #
+      #   set_fixture_class :some_fixture        => SomeModel,
+      #                     'namespaced/fixture' => Another::Model
+      #
+      # The keys must be the fixture names, that coincide with the short paths to the fixture files.
+      #--
+      # It is also possible to pass the class name instead of the class:
+      #   set_fixture_class 'some_fixture' => 'SomeModel'
+      # I think this option is redundant, i propose to deprecate it.
+      # Isn't it easier to always pass the class itself?
+      # (2011-12-20 alexeymuranov)
+      #++
       def set_fixture_class(class_names = {})
-        self.fixture_class_names = self.fixture_class_names.merge(class_names)
+        self.fixture_class_names = self.fixture_class_names.merge(class_names.stringify_keys)
       end
 
       def fixtures(*fixture_names)
@@ -781,9 +789,9 @@ module ActiveRecord
         fixture_names = Array.wrap(fixture_names || fixture_table_names)
         methods = Module.new do
           fixture_names.each do |fixture_name|
-            fixture_name = fixture_name.to_s.tr('./', '_')
+            accessor_name = fixture_name.tr('/', '_').to_sym
 
-            define_method(fixture_name) do |*fixtures|
+            define_method(accessor_name) do |*fixtures|
               force_reload = fixtures.pop if fixtures.last == true || fixtures.last == :reload
 
               @fixture_cache[fixture_name] ||= {}
@@ -796,13 +804,13 @@ module ActiveRecord
                     @fixture_cache[fixture_name][fixture] ||= @loaded_fixtures[fixture_name][fixture.to_s].find
                   end
                 else
-                  raise StandardError, "No fixture with name '#{fixture}' found for table '#{fixture_name}'"
+                  raise StandardError, "No entry named '#{fixture}' found for fixture collection '#{fixture_name}'"
                 end
               end
 
               instances.size == 1 ? instances.first : instances
             end
-            private fixture_name
+            private accessor_name
           end
         end
         include methods
@@ -832,6 +840,7 @@ module ActiveRecord
       end
 
       @fixture_cache = {}
+      @fixture_connections = []
       @@already_loaded_fixtures ||= {}
 
       # Load fixtures once and begin transaction.
@@ -842,9 +851,12 @@ module ActiveRecord
           @loaded_fixtures = load_fixtures
           @@already_loaded_fixtures[self.class] = @loaded_fixtures
         end
-        ActiveRecord::Base.connection.increment_open_transactions
-        ActiveRecord::Base.connection.transaction_joinable = false
-        ActiveRecord::Base.connection.begin_db_transaction
+        @fixture_connections = enlist_fixture_connections
+        @fixture_connections.each do |connection|
+          connection.increment_open_transactions
+          connection.transaction_joinable = false
+          connection.begin_db_transaction
+        end
       # Load fixtures for every test.
       else
         ActiveRecord::Fixtures.reset_cache
@@ -864,13 +876,22 @@ module ActiveRecord
       end
 
       # Rollback changes if a transaction is active.
-      if run_in_transaction? && ActiveRecord::Base.connection.open_transactions != 0
-        ActiveRecord::Base.connection.rollback_db_transaction
-        ActiveRecord::Base.connection.decrement_open_transactions
+      if run_in_transaction?
+        @fixture_connections.each do |connection|
+          if connection.open_transactions != 0
+            connection.rollback_db_transaction
+            connection.decrement_open_transactions
+          end
+        end
+        @fixture_connections.clear
       end
       ActiveRecord::Base.clear_active_connections!
     end
 
+    def enlist_fixture_connections
+      ActiveRecord::Base.connection_handler.connection_pools.values.map(&:connection)
+    end
+
     private
       def load_fixtures
         fixtures = ActiveRecord::Fixtures.create_fixtures(fixture_path, fixture_table_names, fixture_class_names)
diff --git a/activerecord/lib/active_record/identity_map.rb b/activerecord/lib/active_record/identity_map.rb
index b15b5a8133..680d9ffea0 100644
--- a/activerecord/lib/active_record/identity_map.rb
+++ b/activerecord/lib/active_record/identity_map.rb
@@ -111,13 +111,12 @@ module ActiveRecord
     # model object.
     def reinit_with(coder)
       @attributes_cache = {}
-      dirty = @changed_attributes.keys
-      @attributes.update(coder['attributes'].except(*dirty))
+      dirty      = @changed_attributes.keys
+      attributes = self.class.initialize_attributes(coder['attributes'].except(*dirty))
+      @attributes.update(attributes)
       @changed_attributes.update(coder['attributes'].slice(*dirty))
       @changed_attributes.delete_if{|k,v| v.eql? @attributes[k]}
 
-      set_serialized_attributes
-
       run_callbacks :find
 
       self
diff --git a/activerecord/lib/active_record/inheritance.rb b/activerecord/lib/active_record/inheritance.rb
new file mode 100644
index 0000000000..eaa7deac5a
--- /dev/null
+++ b/activerecord/lib/active_record/inheritance.rb
@@ -0,0 +1,182 @@
+require 'active_support/concern'
+
+module ActiveRecord
+  module Inheritance
+    extend ActiveSupport::Concern
+
+    included do
+      # Determine whether to store the full constant name including namespace when using STI
+      config_attribute :store_full_sti_class
+      self.store_full_sti_class = true
+    end
+
+    module ClassMethods
+      # True if this isn't a concrete subclass needing a STI type condition.
+      def descends_from_active_record?
+        sup = active_record_super
+
+        if sup.abstract_class?
+          sup.descends_from_active_record?
+        elsif self == Base
+          false
+        else
+          [Base, Model].include?(sup) || !columns_hash.include?(inheritance_column)
+        end
+      end
+
+      def finder_needs_type_condition? #:nodoc:
+        # This is like this because benchmarking justifies the strange :false stuff
+        :true == (@finder_needs_type_condition ||= descends_from_active_record? ? :false : :true)
+      end
+
+      def symbolized_base_class
+        @symbolized_base_class ||= base_class.to_s.to_sym
+      end
+
+      def symbolized_sti_name
+        @symbolized_sti_name ||= sti_name.present? ? sti_name.to_sym : symbolized_base_class
+      end
+
+      # Returns the base AR subclass that this class descends from. If A
+      # extends AR::Base, A.base_class will return A. If B descends from A
+      # through some arbitrarily deep hierarchy, B.base_class will return A.
+      #
+      # If B < A and C < B and if A is an abstract_class then both B.base_class
+      # and C.base_class would return B as the answer since A is an abstract_class.
+      def base_class
+        class_of_active_record_descendant(self)
+      end
+
+      # Set this to true if this is an abstract class (see <tt>abstract_class?</tt>).
+      attr_accessor :abstract_class
+
+      # Returns whether this class is an abstract class or not.
+      def abstract_class?
+        defined?(@abstract_class) && @abstract_class == true
+      end
+
+      def sti_name
+        store_full_sti_class ? name : name.demodulize
+      end
+
+      # Finder methods must instantiate through this method to work with the
+      # single-table inheritance model that makes it possible to create
+      # objects of different types from the same table.
+      def instantiate(record)
+        sti_class = find_sti_class(record[inheritance_column])
+        record_id = sti_class.primary_key && record[sti_class.primary_key]
+
+        if ActiveRecord::IdentityMap.enabled? && record_id
+          if (column = sti_class.columns_hash[sti_class.primary_key]) && column.number?
+            record_id = record_id.to_i
+          end
+          if instance = IdentityMap.get(sti_class, record_id)
+            instance.reinit_with('attributes' => record)
+          else
+            instance = sti_class.allocate.init_with('attributes' => record)
+            IdentityMap.add(instance)
+          end
+        else
+          instance = sti_class.allocate.init_with('attributes' => record)
+        end
+
+        instance
+      end
+
+      # For internal use.
+      #
+      # If this class includes ActiveRecord::Model then it won't have a
+      # superclass. So this provides a way to get to the 'root' (ActiveRecord::Model).
+      def active_record_super #:nodoc:
+        superclass < Model ? superclass : Model
+      end
+
+      protected
+
+      # Returns the class descending directly from ActiveRecord::Base or an
+      # abstract class, if any, in the inheritance hierarchy.
+      def class_of_active_record_descendant(klass)
+        unless klass < Model
+          raise ActiveRecordError, "#{name} doesn't belong in a hierarchy descending from ActiveRecord"
+        end
+
+        sup = klass.active_record_super
+        if [Base, Model].include?(klass) || [Base, Model].include?(sup) || sup.abstract_class?
+          klass
+        else
+          class_of_active_record_descendant(sup)
+        end
+      end
+
+      # Returns the class type of the record using the current module as a prefix. So descendants of
+      # MyApp::Business::Account would appear as MyApp::Business::AccountSubclass.
+      def compute_type(type_name)
+        if type_name.match(/^::/)
+          # If the type is prefixed with a scope operator then we assume that
+          # the type_name is an absolute reference.
+          ActiveSupport::Dependencies.constantize(type_name)
+        else
+          # Build a list of candidates to search for
+          candidates = []
+          name.scan(/::|$/) { candidates.unshift "#{$`}::#{type_name}" }
+          candidates << type_name
+
+          candidates.each do |candidate|
+            begin
+              constant = ActiveSupport::Dependencies.constantize(candidate)
+              return constant if candidate == constant.to_s
+            rescue NameError => e
+              # We don't want to swallow NoMethodError < NameError errors
+              raise e unless e.instance_of?(NameError)
+            end
+          end
+
+          raise NameError, "uninitialized constant #{candidates.first}"
+        end
+      end
+
+      private
+
+      def find_sti_class(type_name)
+        if type_name.blank? || !columns_hash.include?(inheritance_column)
+          self
+        else
+          begin
+            if store_full_sti_class
+              ActiveSupport::Dependencies.constantize(type_name)
+            else
+              compute_type(type_name)
+            end
+          rescue NameError
+            raise SubclassNotFound,
+              "The single-table inheritance mechanism failed to locate the subclass: '#{type_name}'. " +
+              "This error is raised because the column '#{inheritance_column}' is reserved for storing the class in case of inheritance. " +
+              "Please rename this column if you didn't intend it to be used for storing the inheritance class " +
+              "or overwrite #{name}.inheritance_column to use another column for that information."
+          end
+        end
+      end
+
+      def type_condition(table = arel_table)
+        sti_column = table[inheritance_column.to_sym]
+        sti_names  = ([self] + descendants).map { |model| model.sti_name }
+
+        sti_column.in(sti_names)
+      end
+    end
+
+    private
+
+    # Sets the attribute used for single table inheritance to this class name if this is not the
+    # ActiveRecord::Base descendant.
+    # Considering the hierarchy Reply < Message < ActiveRecord::Base, this makes it possible to
+    # do Reply.new without having to set <tt>Reply[Reply.inheritance_column] = "Reply"</tt> yourself.
+    # No such attribute would be set for objects of the Message class in that example.
+    def ensure_proper_type
+      klass = self.class
+      if klass.finder_needs_type_condition?
+        write_attribute(klass.inheritance_column, klass.sti_name)
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/integration.rb b/activerecord/lib/active_record/integration.rb
new file mode 100644
index 0000000000..2c42f4cca5
--- /dev/null
+++ b/activerecord/lib/active_record/integration.rb
@@ -0,0 +1,49 @@
+module ActiveRecord
+  module Integration
+    # Returns a String, which Action Pack uses for constructing an URL to this
+    # object. The default implementation returns this record's id as a String,
+    # or nil if this record's unsaved.
+    #
+    # For example, suppose that you have a User model, and that you have a
+    # <tt>resources :users</tt> route. Normally, +user_path+ will
+    # construct a path with the user object's 'id' in it:
+    #
+    #   user = User.find_by_name('Phusion')
+    #   user_path(user)  # => "/users/1"
+    #
+    # You can override +to_param+ in your model to make +user_path+ construct
+    # a path using the user's name instead of the user's id:
+    #
+    #   class User < ActiveRecord::Base
+    #     def to_param  # overridden
+    #       name
+    #     end
+    #   end
+    #
+    #   user = User.find_by_name('Phusion')
+    #   user_path(user)  # => "/users/Phusion"
+    def to_param
+      # We can't use alias_method here, because method 'id' optimizes itself on the fly.
+      id && id.to_s # Be sure to stringify the id for routes
+    end
+
+    # Returns a cache key that can be used to identify this record.
+    #
+    # ==== Examples
+    #
+    #   Product.new.cache_key     # => "products/new"
+    #   Product.find(5).cache_key # => "products/5" (updated_at not available)
+    #   Person.find(5).cache_key  # => "people/5-20071224150000" (updated_at available)
+    def cache_key
+      case
+      when new_record?
+        "#{self.class.model_name.cache_key}/new"
+      when timestamp = self[:updated_at]
+        timestamp = timestamp.utc.to_s(:number)
+        "#{self.class.model_name.cache_key}/#{id}-#{timestamp}"
+      else
+        "#{self.class.model_name.cache_key}/#{id}"
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/locking/optimistic.rb b/activerecord/lib/active_record/locking/optimistic.rb
index d9ad7e4132..e643c0d437 100644
--- a/activerecord/lib/active_record/locking/optimistic.rb
+++ b/activerecord/lib/active_record/locking/optimistic.rb
@@ -37,6 +37,9 @@ module ActiveRecord
     # You're then responsible for dealing with the conflict by rescuing the exception and either rolling back, merging,
     # or otherwise apply the business logic needed to resolve the conflict.
     #
+    # This locking mechanism will function inside a single Ruby process. To make it work across all
+    # web requests, the recommended approach is to add +lock_version+ as a hidden field to your form.
+    #
     # You must ensure that your database schema defaults the +lock_version+ column to 0.
     #
     # This behavior can be turned off by setting <tt>ActiveRecord::Base.lock_optimistically = false</tt>.
@@ -46,12 +49,8 @@ module ActiveRecord
       extend ActiveSupport::Concern
 
       included do
-        cattr_accessor :lock_optimistically, :instance_writer => false
+        config_attribute :lock_optimistically, :global => true
         self.lock_optimistically = true
-
-        class << self
-          alias_method :locking_column=, :set_locking_column
-        end
       end
 
       def locking_enabled? #:nodoc:
@@ -65,21 +64,6 @@ module ActiveRecord
           send(lock_col + '=', previous_lock_value + 1)
         end
 
-        def attributes_from_column_definition
-          result = super
-
-          # If the locking column has no default value set,
-          # start the lock version at zero. Note we can't use
-          # <tt>locking_enabled?</tt> at this point as
-          # <tt>@attributes</tt> may not have been initialized yet.
-
-          if result.key?(self.class.locking_column) && lock_optimistically
-            result[self.class.locking_column] ||= 0
-          end
-
-          result
-        end
-
         def update(attribute_names = @attributes.keys) #:nodoc:
           return super unless locking_enabled?
           return 0 if attribute_names.empty?
@@ -103,7 +87,7 @@ module ActiveRecord
             affected_rows = connection.update stmt
 
             unless affected_rows == 1
-              raise ActiveRecord::StaleObjectError, "Attempted to update a stale object: #{self.class.name}"
+              raise ActiveRecord::StaleObjectError.new(self, "update")
             end
 
             affected_rows
@@ -127,7 +111,7 @@ module ActiveRecord
             affected_rows = self.class.unscoped.where(predicate).delete_all
 
             unless affected_rows == 1
-              raise ActiveRecord::StaleObjectError, "Attempted to delete a stale object: #{self.class.name}"
+              raise ActiveRecord::StaleObjectError.new(self, "destroy")
             end
           end
 
@@ -146,14 +130,15 @@ module ActiveRecord
         end
 
         # Set the column to use for optimistic locking. Defaults to +lock_version+.
-        def set_locking_column(value = nil, &block)
-          define_attr_method :locking_column, value, &block
-          value
+        def locking_column=(value)
+          @original_locking_column = @locking_column if defined?(@locking_column)
+          @locking_column          = value.to_s
         end
 
         # The version column used for optimistic locking. Defaults to +lock_version+.
         def locking_column
-          reset_locking_column
+          reset_locking_column unless defined?(@locking_column)
+          @locking_column
         end
 
         # Quote the column name used for optimistic locking.
@@ -163,7 +148,7 @@ module ActiveRecord
 
         # Reset the column used for optimistic locking back to the +lock_version+ default.
         def reset_locking_column
-          set_locking_column DEFAULT_LOCKING_COLUMN
+          self.locking_column = DEFAULT_LOCKING_COLUMN
         end
 
         # Make sure the lock version column gets updated when counters are
@@ -172,6 +157,18 @@ module ActiveRecord
           counters = counters.merge(locking_column => 1) if locking_enabled?
           super
         end
+
+        # If the locking column has no default value set,
+        # start the lock version at zero. Note we can't use
+        # <tt>locking_enabled?</tt> at this point as
+        # <tt>@attributes</tt> may not have been initialized yet.
+        def initialize_attributes(attributes) #:nodoc:
+          if attributes.key?(locking_column) && lock_optimistically
+            attributes[locking_column] ||= 0
+          end
+
+          attributes
+        end
       end
     end
   end
diff --git a/activerecord/lib/active_record/log_subscriber.rb b/activerecord/lib/active_record/log_subscriber.rb
index 3a015ee8c2..a25f2c7bca 100644
--- a/activerecord/lib/active_record/log_subscriber.rb
+++ b/activerecord/lib/active_record/log_subscriber.rb
@@ -26,9 +26,9 @@ module ActiveRecord
 
       return if 'SCHEMA' == payload[:name]
 
-      name    = '%s (%.1fms)' % [payload[:name], event.duration]
-      sql     = payload[:sql].squeeze(' ')
-      binds   = nil
+      name  = '%s (%.1fms)' % [payload[:name], event.duration]
+      sql   = payload[:sql].squeeze(' ')
+      binds = nil
 
       unless (payload[:binds] || []).empty?
         binds = "  " + payload[:binds].map { |col,v|
diff --git a/activerecord/lib/active_record/migration.rb b/activerecord/lib/active_record/migration.rb
index 7166f1b82a..46464783fd 100644
--- a/activerecord/lib/active_record/migration.rb
+++ b/activerecord/lib/active_record/migration.rb
@@ -112,12 +112,13 @@ module ActiveRecord
   #   a column but keeps the type and content.
   # * <tt>change_column(table_name, column_name, type, options)</tt>:  Changes
   #   the column to a different type using the same parameters as add_column.
-  # * <tt>remove_column(table_name, column_name)</tt>: Removes the column named
-  #   +column_name+ from the table called +table_name+.
+  # * <tt>remove_column(table_name, column_names)</tt>: Removes the column listed in
+  #   +column_names+ from the table called +table_name+.
   # * <tt>add_index(table_name, column_names, options)</tt>: Adds a new index
   #   with the name of the column. Other options include
-  #   <tt>:name</tt> and <tt>:unique</tt> (e.g.
-  #   <tt>{ :name => "users_name_index", :unique => true }</tt>).
+  #   <tt>:name</tt>, <tt>:unique</tt> (e.g.
+  #   <tt>{ :name => "users_name_index", :unique => true }</tt>) and <tt>:order</tt>
+  #   (e.g. { :order => {:name => :desc} }</tt>).
   # * <tt>remove_index(table_name, :column => column_name)</tt>: Removes the index
   #   specified by +column_name+.
   # * <tt>remove_index(table_name, :name => index_name)</tt>: Removes the index
@@ -301,7 +302,7 @@ module ActiveRecord
   #
   #   class TenderloveMigration < ActiveRecord::Migration
   #     def change
-  #       create_table(:horses) do
+  #       create_table(:horses) do |t|
   #         t.column :content, :text
   #         t.column :remind_at, :datetime
   #       end
@@ -442,6 +443,7 @@ module ActiveRecord
       say_with_time "#{method}(#{arg_list})" do
         unless arguments.empty? || method == :execute
           arguments[0] = Migrator.proper_table_name(arguments.first)
+          arguments[1] = Migrator.proper_table_name(arguments.second) if method == :rename_table
         end
         return super unless connection.respond_to?(method)
         connection.send(method, *arguments, &block)
@@ -455,26 +457,28 @@ module ActiveRecord
 
       destination_migrations = ActiveRecord::Migrator.migrations(destination)
       last = destination_migrations.last
-      sources.each do |name, path|
+      sources.each do |scope, path|
         source_migrations = ActiveRecord::Migrator.migrations(path)
 
         source_migrations.each do |migration|
           source = File.read(migration.filename)
-          source = "# This migration comes from #{name} (originally #{migration.version})\n#{source}"
+          source = "# This migration comes from #{scope} (originally #{migration.version})\n#{source}"
 
           if duplicate = destination_migrations.detect { |m| m.name == migration.name }
-            options[:on_skip].call(name, migration) if File.read(duplicate.filename) != source && options[:on_skip]
+            if options[:on_skip] && duplicate.scope != scope.to_s
+              options[:on_skip].call(scope, migration)
+            end
             next
           end
 
           migration.version = next_migration_number(last ? last.version + 1 : 0).to_i
-          new_path = File.join(destination, "#{migration.version}_#{migration.name.underscore}.rb")
+          new_path = File.join(destination, "#{migration.version}_#{migration.name.underscore}.#{scope}.rb")
           old_path, migration.filename = migration.filename, new_path
           last = migration
 
-          FileUtils.cp(old_path, migration.filename)
+          File.open(migration.filename, "w") { |f| f.write source }
           copied << migration
-          options[:on_copy].call(name, migration, old_path) if options[:on_copy]
+          options[:on_copy].call(scope, migration, old_path) if options[:on_copy]
           destination_migrations << migration
         end
       end
@@ -493,9 +497,9 @@ module ActiveRecord
 
   # MigrationProxy is used to defer loading of the actual migration classes
   # until they are needed
-  class MigrationProxy < Struct.new(:name, :version, :filename)
+  class MigrationProxy < Struct.new(:name, :version, :filename, :scope)
 
-    def initialize(name, version, filename)
+    def initialize(name, version, filename, scope)
       super
       @migration = nil
     end
@@ -524,16 +528,16 @@ module ActiveRecord
       attr_writer :migrations_paths
       alias :migrations_path= :migrations_paths=
 
-      def migrate(migrations_paths, target_version = nil)
+      def migrate(migrations_paths, target_version = nil, &block)
         case
           when target_version.nil?
-            up(migrations_paths, target_version)
+            up(migrations_paths, target_version, &block)
           when current_version == 0 && target_version == 0
             []
           when current_version > target_version
-            down(migrations_paths, target_version)
+            down(migrations_paths, target_version, &block)
           else
-            up(migrations_paths, target_version)
+            up(migrations_paths, target_version, &block)
         end
       end
 
@@ -545,12 +549,12 @@ module ActiveRecord
         move(:up, migrations_paths, steps)
       end
 
-      def up(migrations_paths, target_version = nil)
-        self.new(:up, migrations_paths, target_version).migrate
+      def up(migrations_paths, target_version = nil, &block)
+        self.new(:up, migrations_paths, target_version).migrate(&block)
       end
 
-      def down(migrations_paths, target_version = nil)
-        self.new(:down, migrations_paths, target_version).migrate
+      def down(migrations_paths, target_version = nil, &block)
+        self.new(:down, migrations_paths, target_version).migrate(&block)
       end
 
       def run(direction, migrations_paths, target_version)
@@ -590,15 +594,16 @@ module ActiveRecord
         migrations_paths.first
       end
 
-      def migrations(paths)
+      def migrations(paths, subdirectories = true)
         paths = Array.wrap(paths)
 
-        files = Dir[*paths.map { |p| "#{p}/[0-9]*_*.rb" }]
+        glob = subdirectories ? "**/" : ""
+        files = Dir[*paths.map { |p| "#{p}/#{glob}[0-9]*_*.rb" }]
 
         seen = Hash.new false
 
         migrations = files.map do |file|
-          version, name = file.scan(/([0-9]+)_([_a-z0-9]*).rb/).first
+          version, name, scope = file.scan(/([0-9]+)_([_a-z0-9]*)\.?([_a-z0-9]*)?.rb/).first
 
           raise IllegalMigrationNameError.new(file) unless version
           version = version.to_i
@@ -609,7 +614,7 @@ module ActiveRecord
 
           seen[version] = seen[name] = true
 
-          MigrationProxy.new(name, version, file)
+          MigrationProxy.new(name, version, file, scope)
         end
 
         migrations.sort_by(&:version)
@@ -652,7 +657,7 @@ module ActiveRecord
       end
     end
 
-    def migrate
+    def migrate(&block)
       current = migrations.detect { |m| m.version == current_version }
       target = migrations.detect { |m| m.version == @target_version }
 
@@ -669,6 +674,10 @@ module ActiveRecord
 
       ran = []
       runnable.each do |migration|
+        if block && !block.call(migration)
+          next
+        end
+
         Base.logger.info "Migrating to #{migration.name} (#{migration.version})" if Base.logger
 
         seen = migrated.include?(migration.version.to_i)
diff --git a/activerecord/lib/active_record/model.rb b/activerecord/lib/active_record/model.rb
new file mode 100644
index 0000000000..86de5ab2fa
--- /dev/null
+++ b/activerecord/lib/active_record/model.rb
@@ -0,0 +1,109 @@
+require 'active_support/deprecation'
+
+module ActiveRecord
+  # <tt>ActiveRecord::Model</tt> can be included into a class to add Active Record persistence.
+  # This is an alternative to inheriting from <tt>ActiveRecord::Base</tt>. Example:
+  #
+  #     class Post
+  #       include ActiveRecord::Model
+  #     end
+  #
+  module Model
+    module ClassMethods #:nodoc:
+      include ActiveSupport::Callbacks::ClassMethods
+      include ActiveModel::Naming
+      include QueryCache::ClassMethods
+      include ActiveSupport::Benchmarkable
+      include ActiveSupport::DescendantsTracker
+
+      include Querying
+      include Translation
+      include DynamicMatchers
+      include CounterCache
+      include Explain
+      include ConnectionHandling
+    end
+
+    def self.included(base)
+      return if base.singleton_class < ClassMethods
+
+      base.class_eval do
+        extend ClassMethods
+        Callbacks::Register.setup(self)
+        initialize_generated_modules unless self == Base
+      end
+    end
+
+    extend ActiveModel::Configuration
+    extend ActiveModel::Callbacks
+    extend ActiveModel::MassAssignmentSecurity::ClassMethods
+    extend ActiveModel::AttributeMethods::ClassMethods
+    extend Callbacks::Register
+    extend Explain
+    extend ConnectionHandling
+
+    def self.extend(*modules)
+      ClassMethods.send(:include, *modules)
+    end
+
+    include Persistence
+    include ReadonlyAttributes
+    include ModelSchema
+    include Inheritance
+    include Scoping
+    include Sanitization
+    include Integration
+    include AttributeAssignment
+    include ActiveModel::Conversion
+    include Validations
+    include Locking::Optimistic, Locking::Pessimistic
+    include AttributeMethods
+    include Callbacks, ActiveModel::Observing, Timestamp
+    include Associations
+    include IdentityMap
+    include ActiveModel::SecurePassword
+    include AutosaveAssociation, NestedAttributes
+    include Aggregations, Transactions, Reflection, Serialization, Store
+    include Core
+
+    class << self
+      def arel_engine
+        self
+      end
+
+      def abstract_class?
+        false
+      end
+
+      def inheritance_column
+        'type'
+      end
+    end
+
+    module DeprecationProxy #:nodoc:
+      class << self
+        instance_methods.each { |m| undef_method m unless m =~ /^__|^object_id$|^instance_eval$/ }
+
+        def method_missing(name, *args, &block)
+          if Model.respond_to?(name)
+            Model.send(name, *args, &block)
+          else
+            ActiveSupport::Deprecation.warn(
+              "The object passed to the active_record load hook was previously ActiveRecord::Base " \
+              "(a Class). Now it is ActiveRecord::Model (a Module). You have called `#{name}' which " \
+              "is only defined on ActiveRecord::Base. Please change your code so that it works with " \
+              "a module rather than a class. (Model is included in Base, so anything added to Model " \
+              "will be available on Base as well.)"
+            )
+            Base.send(name, *args, &block)
+          end
+        end
+
+        alias send method_missing
+      end
+    end
+  end
+
+  # Load Base at this point, because the active_record load hook is run in that file.
+  Base
+end
diff --git a/activerecord/lib/active_record/model_schema.rb b/activerecord/lib/active_record/model_schema.rb
new file mode 100644
index 0000000000..c1a8583119
--- /dev/null
+++ b/activerecord/lib/active_record/model_schema.rb
@@ -0,0 +1,303 @@
+require 'active_support/concern'
+require 'active_support/core_ext/class/attribute_accessors'
+
+module ActiveRecord
+  module ModelSchema
+    extend ActiveSupport::Concern
+
+    included do
+      ##
+      # :singleton-method:
+      # Accessor for the prefix type that will be prepended to every primary key column name.
+      # The options are :table_name and :table_name_with_underscore. If the first is specified,
+      # the Product class will look for "productid" instead of "id" as the primary column. If the
+      # latter is specified, the Product class will look for "product_id" instead of "id". Remember
+      # that this is a global setting for all Active Records.
+      config_attribute :primary_key_prefix_type, :global => true
+
+      ##
+      # :singleton-method:
+      # Accessor for the name of the prefix string to prepend to every table name. So if set
+      # to "basecamp_", all table names will be named like "basecamp_projects", "basecamp_people",
+      # etc. This is a convenient way of creating a namespace for tables in a shared database.
+      # By default, the prefix is the empty string.
+      #
+      # If you are organising your models within modules you can add a prefix to the models within
+      # a namespace by defining a singleton method in the parent module called table_name_prefix which
+      # returns your chosen prefix.
+      config_attribute :table_name_prefix
+      self.table_name_prefix = ""
+
+      ##
+      # :singleton-method:
+      # Works like +table_name_prefix+, but appends instead of prepends (set to "_basecamp" gives "projects_basecamp",
+      # "people_basecamp"). By default, the suffix is the empty string.
+      config_attribute :table_name_suffix
+      self.table_name_suffix = ""
+
+      ##
+      # :singleton-method:
+      # Indicates whether table names should be the pluralized versions of the corresponding class names.
+      # If true, the default table name for a Product class will be +products+. If false, it would just be +product+.
+      # See table_name for the full rules on table/class naming. This is true, by default.
+      config_attribute :pluralize_table_names
+      self.pluralize_table_names = true
+    end
+
+    module ClassMethods
+      # Guesses the table name (in forced lower-case) based on the name of the class in the
+      # inheritance hierarchy descending directly from ActiveRecord::Base. So if the hierarchy
+      # looks like: Reply < Message < ActiveRecord::Base, then Message is used
+      # to guess the table name even when called on Reply. The rules used to do the guess
+      # are handled by the Inflector class in Active Support, which knows almost all common
+      # English inflections. You can add new inflections in config/initializers/inflections.rb.
+      #
+      # Nested classes are given table names prefixed by the singular form of
+      # the parent's table name. Enclosing modules are not considered.
+      #
+      # ==== Examples
+      #
+      #   class Invoice < ActiveRecord::Base
+      #   end
+      #
+      #   file                  class               table_name
+      #   invoice.rb            Invoice             invoices
+      #
+      #   class Invoice < ActiveRecord::Base
+      #     class Lineitem < ActiveRecord::Base
+      #     end
+      #   end
+      #
+      #   file                  class               table_name
+      #   invoice.rb            Invoice::Lineitem   invoice_lineitems
+      #
+      #   module Invoice
+      #     class Lineitem < ActiveRecord::Base
+      #     end
+      #   end
+      #
+      #   file                  class               table_name
+      #   invoice/lineitem.rb   Invoice::Lineitem   lineitems
+      #
+      # Additionally, the class-level +table_name_prefix+ is prepended and the
+      # +table_name_suffix+ is appended. So if you have "myapp_" as a prefix,
+      # the table name guess for an Invoice class becomes "myapp_invoices".
+      # Invoice::Lineitem becomes "myapp_invoice_lineitems".
+      #
+      # You can also set your own table name explicitly:
+      #
+      #   class Mouse < ActiveRecord::Base
+      #     self.table_name = "mice"
+      #   end
+      #
+      # Alternatively, you can override the table_name method to define your
+      # own computation. (Possibly using <tt>super</tt> to manipulate the default
+      # table name.) Example:
+      #
+      #   class Post < ActiveRecord::Base
+      #     def self.table_name
+      #       "special_" + super
+      #     end
+      #   end
+      #   Post.table_name # => "special_posts"
+      def table_name
+        reset_table_name unless defined?(@table_name)
+        @table_name
+      end
+
+      # Sets the table name explicitly. Example:
+      #
+      #   class Project < ActiveRecord::Base
+      #     self.table_name = "project"
+      #   end
+      #
+      # You can also just define your own <tt>self.table_name</tt> method; see
+      # the documentation for ActiveRecord::Base#table_name.
+      def table_name=(value)
+        @original_table_name = @table_name if defined?(@table_name)
+        @table_name          = value
+        @quoted_table_name   = nil
+        @arel_table          = nil
+        @relation            = Relation.new(self, arel_table)
+      end
+
+      # Returns a quoted version of the table name, used to construct SQL statements.
+      def quoted_table_name
+        @quoted_table_name ||= connection.quote_table_name(table_name)
+      end
+
+      # Computes the table name, (re)sets it internally, and returns it.
+      def reset_table_name #:nodoc:
+        if active_record_super.abstract_class?
+          self.table_name = active_record_super.table_name || compute_table_name
+        elsif abstract_class?
+          self.table_name = active_record_super == Base ? nil : active_record_super.table_name
+        else
+          self.table_name = compute_table_name
+        end
+      end
+
+      def full_table_name_prefix #:nodoc:
+        (parents.detect{ |p| p.respond_to?(:table_name_prefix) } || self).table_name_prefix
+      end
+
+      # The name of the column containing the object's class when Single Table Inheritance is used
+      def inheritance_column
+        (@inheritance_column ||= nil) || active_record_super.inheritance_column
+      end
+
+      # Sets the value of inheritance_column
+      def inheritance_column=(value)
+        @original_inheritance_column = inheritance_column
+        @inheritance_column          = value.to_s
+      end
+
+      def sequence_name
+        if base_class == self
+          @sequence_name ||= reset_sequence_name
+        else
+          (@sequence_name ||= nil) || base_class.sequence_name
+        end
+      end
+
+      def reset_sequence_name #:nodoc:
+        self.sequence_name = connection.default_sequence_name(table_name, primary_key)
+      end
+
+      # Sets the name of the sequence to use when generating ids to the given
+      # value, or (if the value is nil or false) to the value returned by the
+      # given block. This is required for Oracle and is useful for any
+      # database which relies on sequences for primary key generation.
+      #
+      # If a sequence name is not explicitly set when using Oracle or Firebird,
+      # it will default to the commonly used pattern of: #{table_name}_seq
+      #
+      # If a sequence name is not explicitly set when using PostgreSQL, it
+      # will discover the sequence corresponding to your primary key for you.
+      #
+      #   class Project < ActiveRecord::Base
+      #     self.sequence_name = "projectseq"   # default would have been "project_seq"
+      #   end
+      def sequence_name=(value)
+        @original_sequence_name = @sequence_name if defined?(@sequence_name)
+        @sequence_name          = value.to_s
+      end
+
+      # Indicates whether the table associated with this class exists
+      def table_exists?
+        connection.schema_cache.table_exists?(table_name)
+      end
+
+      # Returns an array of column objects for the table associated with this class.
+      def columns
+        @columns ||= connection.schema_cache.columns[table_name].map do |col|
+          col = col.dup
+          col.primary = (col.name == primary_key)
+          col
+        end
+      end
+
+      # Returns a hash of column objects for the table associated with this class.
+      def columns_hash
+        @columns_hash ||= Hash[columns.map { |c| [c.name, c] }]
+      end
+
+      # Returns a hash where the keys are column names and the values are
+      # default values when instantiating the AR object for this table.
+      def column_defaults
+        @column_defaults ||= Hash[columns.map { |c| [c.name, c.default] }]
+      end
+
+      # Returns an array of column names as strings.
+      def column_names
+        @column_names ||= columns.map { |column| column.name }
+      end
+
+      # Returns an array of column objects where the primary id, all columns ending in "_id" or "_count",
+      # and columns used for single table inheritance have been removed.
+      def content_columns
+        @content_columns ||= columns.reject { |c| c.primary || c.name =~ /(_id|_count)$/ || c.name == inheritance_column }
+      end
+
+      # Returns a hash of all the methods added to query each of the columns in the table with the name of the method as the key
+      # and true as the value. This makes it possible to do O(1) lookups in respond_to? to check if a given method for attribute
+      # is available.
+      def column_methods_hash #:nodoc:
+        @dynamic_methods_hash ||= column_names.inject(Hash.new(false)) do |methods, attr|
+          attr_name = attr.to_s
+          methods[attr.to_sym]       = attr_name
+          methods["#{attr}=".to_sym] = attr_name
+          methods["#{attr}?".to_sym] = attr_name
+          methods["#{attr}_before_type_cast".to_sym] = attr_name
+          methods
+        end
+      end
+
+      # Resets all the cached information about columns, which will cause them
+      # to be reloaded on the next request.
+      #
+      # The most common usage pattern for this method is probably in a migration,
+      # when just after creating a table you want to populate it with some default
+      # values, eg:
+      #
+      #  class CreateJobLevels < ActiveRecord::Migration
+      #    def up
+      #      create_table :job_levels do |t|
+      #        t.integer :id
+      #        t.string :name
+      #
+      #        t.timestamps
+      #      end
+      #
+      #      JobLevel.reset_column_information
+      #      %w{assistant executive manager director}.each do |type|
+      #        JobLevel.create(:name => type)
+      #      end
+      #    end
+      #
+      #    def down
+      #      drop_table :job_levels
+      #    end
+      #  end
+      def reset_column_information
+        connection.clear_cache!
+        undefine_attribute_methods
+        connection.schema_cache.clear_table_cache!(table_name) if table_exists?
+
+        @column_names = @content_columns = @column_defaults = @columns = @columns_hash = nil
+        @dynamic_methods_hash = @inheritance_column = nil
+        @arel_engine = @relation = nil
+      end
+
+      def clear_cache! # :nodoc:
+        connection.schema_cache.clear!
+      end
+
+      private
+
+      # Guesses the table name, but does not decorate it with prefix and suffix information.
+      def undecorated_table_name(class_name = base_class.name)
+        table_name = class_name.to_s.demodulize.underscore
+        table_name = table_name.pluralize if pluralize_table_names
+        table_name
+      end
+
+      # Computes and returns a table name according to default conventions.
+      def compute_table_name
+        base = base_class
+        if self == base
+          # Nested classes are prefixed with singular parent table name.
+          if parent < ActiveRecord::Model && !parent.abstract_class?
+            contained = parent.table_name
+            contained = contained.singularize if parent.pluralize_table_names
+            contained += '_'
+          end
+          "#{full_table_name_prefix}#{contained}#{undecorated_table_name(name)}#{table_name_suffix}"
+        else
+          # STI subclasses always use their superclass' table.
+          base.table_name
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/named_scope.rb b/activerecord/lib/active_record/named_scope.rb
deleted file mode 100644
index 0313abe456..0000000000
--- a/activerecord/lib/active_record/named_scope.rb
+++ /dev/null
@@ -1,200 +0,0 @@
-require 'active_support/core_ext/array'
-require 'active_support/core_ext/hash/except'
-require 'active_support/core_ext/kernel/singleton_class'
-require 'active_support/core_ext/object/blank'
-require 'active_support/core_ext/class/attribute'
-
-module ActiveRecord
-  # = Active Record Named \Scopes
-  module NamedScope
-    extend ActiveSupport::Concern
-
-    module ClassMethods
-      # Returns an anonymous \scope.
-      #
-      #   posts = Post.scoped
-      #   posts.size # Fires "select count(*) from  posts" and returns the count
-      #   posts.each {|p| puts p.name } # Fires "select * from posts" and loads post objects
-      #
-      #   fruits = Fruit.scoped
-      #   fruits = fruits.where(:color => 'red') if options[:red_only]
-      #   fruits = fruits.limit(10) if limited?
-      #
-      # Anonymous \scopes tend to be useful when procedurally generating complex
-      # queries, where passing intermediate values (\scopes) around as first-class
-      # objects is convenient.
-      #
-      # You can define a \scope that applies to all finders using
-      # ActiveRecord::Base.default_scope.
-      def scoped(options = nil)
-        if options
-          scoped.apply_finder_options(options)
-        else
-          if current_scope
-            current_scope.clone
-          else
-            scope = relation.clone
-            scope.default_scoped = true
-            scope
-          end
-        end
-      end
-
-      ##
-      # Collects attributes from scopes that should be applied when creating
-      # an AR instance for the particular class this is called on.
-      def scope_attributes # :nodoc:
-        if current_scope
-          current_scope.scope_for_create
-        else
-          scope = relation.clone
-          scope.default_scoped = true
-          scope.scope_for_create
-        end
-      end
-
-      ##
-      # Are there default attributes associated with this scope?
-      def scope_attributes? # :nodoc:
-        current_scope || default_scopes.any?
-      end
-
-      # Adds a class method for retrieving and querying objects. A \scope represents a narrowing of a database query,
-      # such as <tt>where(:color => :red).select('shirts.*').includes(:washing_instructions)</tt>.
-      #
-      #   class Shirt < ActiveRecord::Base
-      #     scope :red, where(:color => 'red')
-      #     scope :dry_clean_only, joins(:washing_instructions).where('washing_instructions.dry_clean_only = ?', true)
-      #   end
-      #
-      # The above calls to <tt>scope</tt> define class methods Shirt.red and Shirt.dry_clean_only. Shirt.red,
-      # in effect, represents the query <tt>Shirt.where(:color => 'red')</tt>.
-      #
-      # Note that this is simply 'syntactic sugar' for defining an actual class method:
-      #
-      #   class Shirt < ActiveRecord::Base
-      #     def self.red
-      #       where(:color => 'red')
-      #     end
-      #   end
-      #
-      # Unlike <tt>Shirt.find(...)</tt>, however, the object returned by Shirt.red is not an Array; it
-      # resembles the association object constructed by a <tt>has_many</tt> declaration. For instance,
-      # you can invoke <tt>Shirt.red.first</tt>, <tt>Shirt.red.count</tt>, <tt>Shirt.red.where(:size => 'small')</tt>.
-      # Also, just as with the association objects, named \scopes act like an Array, implementing Enumerable;
-      # <tt>Shirt.red.each(&block)</tt>, <tt>Shirt.red.first</tt>, and <tt>Shirt.red.inject(memo, &block)</tt>
-      # all behave as if Shirt.red really was an Array.
-      #
-      # These named \scopes are composable. For instance, <tt>Shirt.red.dry_clean_only</tt> will produce
-      # all shirts that are both red and dry clean only.
-      # Nested finds and calculations also work with these compositions: <tt>Shirt.red.dry_clean_only.count</tt>
-      # returns the number of garments for which these criteria obtain. Similarly with
-      # <tt>Shirt.red.dry_clean_only.average(:thread_count)</tt>.
-      #
-      # All \scopes are available as class methods on the ActiveRecord::Base descendant upon which
-      # the \scopes were defined. But they are also available to <tt>has_many</tt> associations. If,
-      #
-      #   class Person < ActiveRecord::Base
-      #     has_many :shirts
-      #   end
-      #
-      # then <tt>elton.shirts.red.dry_clean_only</tt> will return all of Elton's red, dry clean
-      # only shirts.
-      #
-      # Named \scopes can also be procedural:
-      #
-      #   class Shirt < ActiveRecord::Base
-      #     scope :colored, lambda { |color| where(:color => color) }
-      #   end
-      #
-      # In this example, <tt>Shirt.colored('puce')</tt> finds all puce shirts.
-      #
-      # On Ruby 1.9 you can use the 'stabby lambda' syntax:
-      #
-      #   scope :colored, ->(color) { where(:color => color) }
-      #
-      # Note that scopes defined with \scope will be evaluated when they are defined, rather than
-      # when they are used. For example, the following would be incorrect:
-      #
-      #   class Post < ActiveRecord::Base
-      #     scope :recent, where('published_at >= ?', Time.now - 1.week)
-      #   end
-      #
-      # The example above would be 'frozen' to the <tt>Time.now</tt> value when the <tt>Post</tt>
-      # class was defined, and so the resultant SQL query would always be the same. The correct
-      # way to do this would be via a lambda, which will re-evaluate the scope each time
-      # it is called:
-      #
-      #   class Post < ActiveRecord::Base
-      #     scope :recent, lambda { where('published_at >= ?', Time.now - 1.week) }
-      #   end
-      #
-      # Named \scopes can also have extensions, just as with <tt>has_many</tt> declarations:
-      #
-      #   class Shirt < ActiveRecord::Base
-      #     scope :red, where(:color => 'red') do
-      #       def dom_id
-      #         'red_shirts'
-      #       end
-      #     end
-      #   end
-      #
-      # Scopes can also be used while creating/building a record.
-      #
-      #   class Article < ActiveRecord::Base
-      #     scope :published, where(:published => true)
-      #   end
-      #
-      #   Article.published.new.published    # => true
-      #   Article.published.create.published # => true
-      #
-      # Class methods on your model are automatically available
-      # on scopes. Assuming the following setup:
-      #
-      #   class Article < ActiveRecord::Base
-      #     scope :published, where(:published => true)
-      #     scope :featured, where(:featured => true)
-      #
-      #     def self.latest_article
-      #       order('published_at desc').first
-      #     end
-      #
-      #     def self.titles
-      #       map(&:title)
-      #     end
-      #
-      #   end
-      #
-      # We are able to call the methods like this:
-      #
-      #   Article.published.featured.latest_article
-      #   Article.featured.titles
-
-      def scope(name, scope_options = {})
-        name = name.to_sym
-        valid_scope_name?(name)
-        extension = Module.new(&Proc.new) if block_given?
-
-        scope_proc = lambda do |*args|
-          options = scope_options.respond_to?(:call) ? scope_options.call(*args) : scope_options
-          options = scoped.apply_finder_options(options) if options.is_a?(Hash)
-
-          relation = scoped.merge(options)
-
-          extension ? relation.extending(extension) : relation
-        end
-
-        singleton_class.send(:redefine_method, name, &scope_proc)
-      end
-
-    protected
-
-      def valid_scope_name?(name)
-        if respond_to?(name, true)
-          logger.warn "Creating scope :#{name}. " \
-                      "Overwriting existing method #{self.name}.#{name}."
-        end
-      end
-    end
-  end
-end
diff --git a/activerecord/lib/active_record/nested_attributes.rb b/activerecord/lib/active_record/nested_attributes.rb
index 2dbebfcaf8..a8ee43b598 100644
--- a/activerecord/lib/active_record/nested_attributes.rb
+++ b/activerecord/lib/active_record/nested_attributes.rb
@@ -12,7 +12,7 @@ module ActiveRecord
     extend ActiveSupport::Concern
 
     included do
-      class_attribute :nested_attributes_options, :instance_writer => false
+      config_attribute :nested_attributes_options
       self.nested_attributes_options = {}
     end
 
@@ -220,7 +220,7 @@ module ActiveRecord
     #     validates_presence_of :member
     #   end
     module ClassMethods
-      REJECT_ALL_BLANK_PROC = proc { |attributes| attributes.all? { |_, value| value.blank? } }
+      REJECT_ALL_BLANK_PROC = proc { |attributes| attributes.all? { |key, value| key == '_destroy' || value.blank? } }
 
       # Defines an attributes writer for the specified association(s). If you
       # are using <tt>attr_protected</tt> or <tt>attr_accessible</tt>, then you
@@ -239,7 +239,8 @@ module ActiveRecord
       #   is specified, a record will be built for all attribute hashes that
       #   do not have a <tt>_destroy</tt> value that evaluates to true.
       #   Passing <tt>:all_blank</tt> instead of a Proc will create a proc
-      #   that will reject a record where all the attributes are blank.
+      #   that will reject a record where all the attributes are blank excluding
+      #   any value for _destroy.
       # [:limit]
       #   Allows you to specify the maximum number of the associated records that
       #   can be processed with the nested attributes. If the size of the
diff --git a/activerecord/lib/active_record/persistence.rb b/activerecord/lib/active_record/persistence.rb
index b5dadb929d..09ee2ba61d 100644
--- a/activerecord/lib/active_record/persistence.rb
+++ b/activerecord/lib/active_record/persistence.rb
@@ -1,6 +1,53 @@
+require 'active_support/concern'
+
 module ActiveRecord
   # = Active Record Persistence
   module Persistence
+    extend ActiveSupport::Concern
+
+    module ClassMethods
+      # Creates an object (or multiple objects) and saves it to the database, if validations pass.
+      # The resulting object is returned whether the object was saved successfully to the database or not.
+      #
+      # The +attributes+ parameter can be either a Hash or an Array of Hashes. These Hashes describe the
+      # attributes on the objects that are to be created.
+      #
+      # +create+ respects mass-assignment security and accepts either +:as+ or +:without_protection+ options
+      # in the +options+ parameter.
+      #
+      # ==== Examples
+      #   # Create a single new object
+      #   User.create(:first_name => 'Jamie')
+      #
+      #   # Create a single new object using the :admin mass-assignment security role
+      #   User.create({ :first_name => 'Jamie', :is_admin => true }, :as => :admin)
+      #
+      #   # Create a single new object bypassing mass-assignment security
+      #   User.create({ :first_name => 'Jamie', :is_admin => true }, :without_protection => true)
+      #
+      #   # Create an Array of new objects
+      #   User.create([{ :first_name => 'Jamie' }, { :first_name => 'Jeremy' }])
+      #
+      #   # Create a single object and pass it into a block to set other attributes.
+      #   User.create(:first_name => 'Jamie') do |u|
+      #     u.is_admin = false
+      #   end
+      #
+      #   # Creating an Array of new objects using a block, where the block is executed for each object:
+      #   User.create([{ :first_name => 'Jamie' }, { :first_name => 'Jeremy' }]) do |u|
+      #     u.is_admin = false
+      #   end
+      def create(attributes = nil, options = {}, &block)
+        if attributes.is_a?(Array)
+          attributes.collect { |attr| create(attr, options, &block) }
+        else
+          object = new(attributes, options, &block)
+          object.save
+          object
+        end
+      end
+    end
+
     # Returns true if this object hasn't been saved yet -- that is, a record
     # for the object doesn't exist in the data store yet; otherwise, returns false.
     def new_record?
@@ -12,8 +59,8 @@ module ActiveRecord
       @destroyed
     end
 
-    # Returns if the record is persisted, i.e. it's not a new record and it was
-    # not destroyed.
+    # Returns true if the record is persisted, i.e. it's not a new record and it was
+    # not destroyed, otherwise returns false.
     def persisted?
       !(new_record? || destroyed?)
     end
@@ -114,6 +161,7 @@ module ActiveRecord
       became.instance_variable_set("@attributes_cache", @attributes_cache)
       became.instance_variable_set("@new_record", new_record?)
       became.instance_variable_set("@destroyed", destroyed?)
+      became.instance_variable_set("@errors", errors)
       became.type = klass.name unless self.class.descends_from_active_record?
       became
     end
@@ -161,7 +209,7 @@ module ActiveRecord
       # The following transaction covers any possible database side-effects of the
       # attributes assignment. For example, setting the IDs of a child collection.
       with_transaction_returning_status do
-        self.assign_attributes(attributes, options)
+        assign_attributes(attributes, options)
         save
       end
     end
@@ -172,7 +220,7 @@ module ActiveRecord
       # The following transaction covers any possible database side-effects of the
       # attributes assignment. For example, setting the IDs of a child collection.
       with_transaction_returning_status do
-        self.assign_attributes(attributes, options)
+        assign_attributes(attributes, options)
         save!
       end
     end
@@ -237,7 +285,7 @@ module ActiveRecord
       clear_association_cache
 
       IdentityMap.without do
-        fresh_object = self.class.unscoped { self.class.find(self.id, options) }
+        fresh_object = self.class.unscoped { self.class.find(id, options) }
         @attributes.update(fresh_object.instance_variable_get('@attributes'))
       end
 
@@ -314,19 +362,11 @@ module ActiveRecord
 
       new_id = self.class.unscoped.insert attributes_values
 
-      self.id ||= new_id if self.class.primary_key?
+      self.id ||= new_id if self.class.primary_key
 
       IdentityMap.add(self) if IdentityMap.enabled?
       @new_record = false
       id
     end
-
-    # Initializes the attributes array with keys matching the columns from the linked table and
-    # the values matching the corresponding default value of that column, so
-    # that a new instance, or one populated from a passed-in Hash, still has all the attributes
-    # that instances loaded from the database would.
-    def attributes_from_column_definition
-      self.class.column_defaults.dup
-    end
   end
 end
diff --git a/activerecord/lib/active_record/query_cache.rb b/activerecord/lib/active_record/query_cache.rb
index 10c0dc6f2a..466d148901 100644
--- a/activerecord/lib/active_record/query_cache.rb
+++ b/activerecord/lib/active_record/query_cache.rb
@@ -28,9 +28,10 @@ module ActiveRecord
     end
 
     class BodyProxy # :nodoc:
-      def initialize(original_cache_value, target)
+      def initialize(original_cache_value, target, connection_id)
         @original_cache_value = original_cache_value
         @target               = target
+        @connection_id        = connection_id
       end
 
       def method_missing(method_sym, *arguments, &block)
@@ -48,6 +49,7 @@ module ActiveRecord
       def close
         @target.close if @target.respond_to?(:close)
       ensure
+        ActiveRecord::Base.connection_id = @connection_id
         ActiveRecord::Base.connection.clear_query_cache
         unless @original_cache_value
           ActiveRecord::Base.connection.disable_query_cache!
@@ -60,7 +62,7 @@ module ActiveRecord
       ActiveRecord::Base.connection.enable_query_cache!
 
       status, headers, body = @app.call(env)
-      [status, headers, BodyProxy.new(old, body)]
+      [status, headers, BodyProxy.new(old, body, ActiveRecord::Base.connection_id)]
     rescue Exception => e
       ActiveRecord::Base.connection.clear_query_cache
       unless old
diff --git a/activerecord/lib/active_record/querying.rb b/activerecord/lib/active_record/querying.rb
new file mode 100644
index 0000000000..09da9ad1d1
--- /dev/null
+++ b/activerecord/lib/active_record/querying.rb
@@ -0,0 +1,58 @@
+require 'active_support/core_ext/module/delegation'
+
+module ActiveRecord
+  module Querying
+    delegate :find, :first, :first!, :last, :last!, :all, :exists?, :any?, :many?, :to => :scoped
+    delegate :first_or_create, :first_or_create!, :first_or_initialize, :to => :scoped
+    delegate :destroy, :destroy_all, :delete, :delete_all, :update, :update_all, :to => :scoped
+    delegate :find_each, :find_in_batches, :to => :scoped
+    delegate :select, :group, :order, :except, :reorder, :limit, :offset, :joins,
+             :where, :preload, :eager_load, :includes, :from, :lock, :readonly,
+             :having, :create_with, :uniq, :to => :scoped
+    delegate :count, :average, :minimum, :maximum, :sum, :calculate, :pluck, :to => :scoped
+
+    # Executes a custom SQL query against your database and returns all the results. The results will
+    # be returned as an array with columns requested encapsulated as attributes of the model you call
+    # this method from. If you call <tt>Product.find_by_sql</tt> then the results will be returned in
+    # a Product object with the attributes you specified in the SQL query.
+    #
+    # If you call a complicated SQL query which spans multiple tables the columns specified by the
+    # SELECT will be attributes of the model, whether or not they are columns of the corresponding
+    # table.
+    #
+    # The +sql+ parameter is a full SQL query as a string. It will be called as is, there will be
+    # no database agnostic conversions performed. This should be a last resort because using, for example,
+    # MySQL specific terms will lock you to using that particular database engine or require you to
+    # change your call if you switch engines.
+    #
+    # ==== Examples
+    #   # A simple SQL query spanning multiple tables
+    #   Post.find_by_sql "SELECT p.title, c.author FROM posts p, comments c WHERE p.id = c.post_id"
+    #   > [#<Post:0x36bff9c @attributes={"title"=>"Ruby Meetup", "first_name"=>"Quentin"}>, ...]
+    #
+    #   # You can use the same string replacement techniques as you can with ActiveRecord#find
+    #   Post.find_by_sql ["SELECT title FROM posts WHERE author = ? AND created > ?", author_id, start_date]
+    #   > [#<Post:0x36bff9c @attributes={"title"=>"The Cheap Man Buys Twice"}>, ...]
+    def find_by_sql(sql, binds = [])
+      logging_query_plan do
+        connection.select_all(sanitize_sql(sql), "#{name} Load", binds).collect! { |record| instantiate(record) }
+      end
+    end
+
+    # Returns the result of an SQL statement that should only include a COUNT(*) in the SELECT part.
+    # The use of this method should be restricted to complicated SQL queries that can't be executed
+    # using the ActiveRecord::Calculations class methods. Look into those before using this.
+    #
+    # ==== Parameters
+    #
+    # * +sql+ - An SQL statement which should return a count query from the database, see the example below.
+    #
+    # ==== Examples
+    #
+    #   Product.count_by_sql "SELECT COUNT(*) FROM sales s, customers c WHERE s.customer_id = c.id"
+    def count_by_sql(sql)
+      sql = sanitize_conditions(sql)
+      connection.select_value(sql, "#{name} Count").to_i
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/railtie.rb b/activerecord/lib/active_record/railtie.rb
index 47133e77e8..165d0750dd 100644
--- a/activerecord/lib/active_record/railtie.rb
+++ b/activerecord/lib/active_record/railtie.rb
@@ -22,6 +22,13 @@ module ActiveRecord
     config.app_middleware.insert_after "::ActionDispatch::Callbacks",
       "ActiveRecord::ConnectionAdapters::ConnectionManagement"
 
+    config.action_dispatch.rescue_responses.merge!(
+      'ActiveRecord::RecordNotFound'   => :not_found,
+      'ActiveRecord::StaleObjectError' => :conflict,
+      'ActiveRecord::RecordInvalid'    => :unprocessable_entity,
+      'ActiveRecord::RecordNotSaved'   => :unprocessable_entity
+    )
+
     rake_tasks do
       load "active_record/railties/databases.rake"
     end
@@ -78,18 +85,30 @@ module ActiveRecord
       end
     end
 
-    initializer "active_record.set_dispatch_hooks", :before => :set_clear_dependencies_hook do |app|
-      ActiveSupport.on_load(:active_record) do
-        ActionDispatch::Reloader.to_cleanup do
-          ActiveRecord::Base.clear_reloadable_connections!
-          ActiveRecord::Base.clear_cache!
+    initializer "active_record.set_reloader_hooks" do |app|
+      hook = lambda do
+        ActiveRecord::Base.clear_reloadable_connections!
+        ActiveRecord::Base.clear_cache!
+      end
+
+      if app.config.reload_classes_only_on_change
+        ActiveSupport.on_load(:active_record) do
+          ActionDispatch::Reloader.to_prepare(&hook)
+        end
+      else
+        ActiveSupport.on_load(:active_record) do
+          ActionDispatch::Reloader.to_cleanup(&hook)
         end
       end
     end
 
+    initializer "active_record.add_watchable_files" do |app|
+      config.watchable_files.concat ["#{app.root}/db/schema.rb", "#{app.root}/db/structure.sql"]
+    end
+
     config.after_initialize do
       ActiveSupport.on_load(:active_record) do
-        instantiate_observers
+        ActiveRecord::Base.instantiate_observers
 
         ActionDispatch::Reloader.to_prepare do
           ActiveRecord::Base.instantiate_observers
diff --git a/activerecord/lib/active_record/railties/databases.rake b/activerecord/lib/active_record/railties/databases.rake
index f4a813d704..180424641a 100644
--- a/activerecord/lib/active_record/railties/databases.rake
+++ b/activerecord/lib/active_record/railties/databases.rake
@@ -1,8 +1,8 @@
 require 'active_support/core_ext/object/inclusion'
+require 'active_record'
 
 db_namespace = namespace :db do
   task :load_config => :rails_env do
-    require 'active_record'
     ActiveRecord::Base.configurations = Rails.application.config.database_configuration
     ActiveRecord::Migrator.migrations_paths = Rails.application.paths['db/migrate'].to_a
 
@@ -37,11 +37,8 @@ db_namespace = namespace :db do
 
   desc 'Create the database from config/database.yml for the current Rails.env (use db:create:all to create all dbs in the config)'
   task :create => :load_config do
-    # Make the test database at the same time as the development one, if it exists
-    if Rails.env.development? && ActiveRecord::Base.configurations['test']
-      create_database(ActiveRecord::Base.configurations['test'])
-    end
-    create_database(ActiveRecord::Base.configurations[Rails.env])
+    configs_for_environment.each { |config| create_database(config) }
+    ActiveRecord::Base.establish_connection(configs_for_environment.first)
   end
 
   def mysql_creation_options(config)
@@ -115,8 +112,7 @@ db_namespace = namespace :db do
         end
       end
     else
-      # Bug with 1.9.2 Calling return within begin still executes else
-      $stderr.puts "#{config['database']} already exists" unless config['adapter'] =~ /sqlite/
+      $stderr.puts "#{config['database']} already exists"
     end
   end
 
@@ -138,12 +134,7 @@ db_namespace = namespace :db do
 
   desc 'Drops the database for the current Rails.env (use db:drop:all to drop all databases)'
   task :drop => :load_config do
-    config = ActiveRecord::Base.configurations[Rails.env || 'development']
-    begin
-      drop_database(config)
-    rescue Exception => e
-      $stderr.puts "Couldn't drop #{config['database']} : #{e.inspect}"
-    end
+    configs_for_environment.each { |config| drop_database_and_rescue(config) }
   end
 
   def local_database?(config, &block)
@@ -158,8 +149,19 @@ db_namespace = namespace :db do
   desc "Migrate the database (options: VERSION=x, VERBOSE=false)."
   task :migrate => [:environment, :load_config] do
     ActiveRecord::Migration.verbose = ENV["VERBOSE"] ? ENV["VERBOSE"] == "true" : true
-    ActiveRecord::Migrator.migrate(ActiveRecord::Migrator.migrations_paths, ENV["VERSION"] ? ENV["VERSION"].to_i : nil)
-    db_namespace["schema:dump"].invoke if ActiveRecord::Base.schema_format == :ruby
+    ActiveRecord::Migrator.migrate(ActiveRecord::Migrator.migrations_paths, ENV["VERSION"] ? ENV["VERSION"].to_i : nil) do |migration|
+      ENV["SCOPE"].blank? || (ENV["SCOPE"] == migration.scope)
+    end
+    db_namespace['_dump'].invoke
+  end
+
+  task :_dump do
+    case ActiveRecord::Base.schema_format
+    when :ruby then db_namespace["schema:dump"].invoke
+    when :sql  then db_namespace["structure:dump"].invoke
+    else
+      raise "unknown schema format #{ActiveRecord::Base.schema_format}"
+    end
   end
 
   namespace :migrate do
@@ -182,7 +184,7 @@ db_namespace = namespace :db do
       version = ENV['VERSION'] ? ENV['VERSION'].to_i : nil
       raise 'VERSION is required' unless version
       ActiveRecord::Migrator.run(:up, ActiveRecord::Migrator.migrations_paths, version)
-      db_namespace['schema:dump'].invoke if ActiveRecord::Base.schema_format == :ruby
+      db_namespace['_dump'].invoke
     end
 
     # desc 'Runs the "down" for a given migration VERSION.'
@@ -190,7 +192,7 @@ db_namespace = namespace :db do
       version = ENV['VERSION'] ? ENV['VERSION'].to_i : nil
       raise 'VERSION is required' unless version
       ActiveRecord::Migrator.run(:down, ActiveRecord::Migrator.migrations_paths, version)
-      db_namespace['schema:dump'].invoke if ActiveRecord::Base.schema_format == :ruby
+      db_namespace['_dump'].invoke
     end
 
     desc 'Display status of migrations'
@@ -230,18 +232,21 @@ db_namespace = namespace :db do
   task :rollback => [:environment, :load_config] do
     step = ENV['STEP'] ? ENV['STEP'].to_i : 1
     ActiveRecord::Migrator.rollback(ActiveRecord::Migrator.migrations_paths, step)
-    db_namespace['schema:dump'].invoke if ActiveRecord::Base.schema_format == :ruby
+    db_namespace['_dump'].invoke
   end
 
   # desc 'Pushes the schema to the next version (specify steps w/ STEP=n).'
   task :forward => [:environment, :load_config] do
     step = ENV['STEP'] ? ENV['STEP'].to_i : 1
     ActiveRecord::Migrator.forward(ActiveRecord::Migrator.migrations_paths, step)
-    db_namespace['schema:dump'].invoke if ActiveRecord::Base.schema_format == :ruby
+    db_namespace['_dump'].invoke
   end
 
   # desc 'Drops and recreates the database from db/schema.rb for the current environment and loads the seeds.'
-  task :reset => [ 'db:drop', 'db:setup' ]
+  task :reset => :environment do
+    db_namespace["drop"].invoke
+    db_namespace["setup"].invoke
+  end
 
   # desc "Retrieves the charset for the current environment's database"
   task :charset => :environment do
@@ -280,24 +285,23 @@ db_namespace = namespace :db do
 
   # desc "Raises an error if there are pending migrations"
   task :abort_if_pending_migrations => :environment do
-    if defined? ActiveRecord
-      pending_migrations = ActiveRecord::Migrator.new(:up, ActiveRecord::Migrator.migrations_paths).pending_migrations
+    pending_migrations = ActiveRecord::Migrator.new(:up, ActiveRecord::Migrator.migrations_paths).pending_migrations
 
-      if pending_migrations.any?
-        puts "You have #{pending_migrations.size} pending migrations:"
-        pending_migrations.each do |pending_migration|
-          puts '  %4d %s' % [pending_migration.version, pending_migration.name]
-        end
-        abort %{Run "rake db:migrate" to update your database then try again.}
+    if pending_migrations.any?
+      puts "You have #{pending_migrations.size} pending migrations:"
+      pending_migrations.each do |pending_migration|
+        puts '  %4d %s' % [pending_migration.version, pending_migration.name]
       end
+      abort %{Run `rake db:migrate` to update your database then try again.}
     end
   end
 
   desc 'Create the database, load the schema, and initialize with the seed data (use db:reset to also drop the db first)'
-  task :setup => [ 'db:create', 'db:schema:load', 'db:seed' ]
+  task :setup => ['db:schema:load_if_ruby', 'db:structure:load_if_sql', :seed]
 
   desc 'Load the seed data from db/seeds.rb'
-  task :seed => 'db:abort_if_pending_migrations' do
+  task :seed do
+    db_namespace['abort_if_pending_migrations'].invoke
     Rails.application.load_seed
   end
 
@@ -357,93 +361,125 @@ db_namespace = namespace :db do
       if File.exists?(file)
         load(file)
       else
-        abort %{#{file} doesn't exist yet. Run "rake db:migrate" to create it then try again. If you do not intend to use a database, you should instead alter #{Rails.root}/config/application.rb to limit the frameworks that will be loaded}
+        abort %{#{file} doesn't exist yet. Run `rake db:migrate` to create it then try again. If you do not intend to use a database, you should instead alter #{Rails.root}/config/application.rb to limit the frameworks that will be loaded}
       end
     end
+
+    task :load_if_ruby => 'db:create' do
+      db_namespace["schema:load"].invoke if ActiveRecord::Base.schema_format == :ruby
+    end
   end
 
   namespace :structure do
-    desc 'Dump the database structure to an SQL file'
+    desc 'Dump the database structure to db/structure.sql. Specify another file with DB_STRUCTURE=db/my_structure.sql'
     task :dump => :environment do
       abcs = ActiveRecord::Base.configurations
+      filename = ENV['DB_STRUCTURE'] || File.join(Rails.root, "db", "structure.sql")
       case abcs[Rails.env]['adapter']
       when /mysql/, 'oci', 'oracle'
         ActiveRecord::Base.establish_connection(abcs[Rails.env])
-        File.open("#{Rails.root}/db/#{Rails.env}_structure.sql", "w+") { |f| f << ActiveRecord::Base.connection.structure_dump }
+        File.open(filename, "w:utf-8") { |f| f << ActiveRecord::Base.connection.structure_dump }
       when /postgresql/
-        ENV['PGHOST']     = abcs[Rails.env]['host'] if abcs[Rails.env]['host']
-        ENV['PGPORT']     = abcs[Rails.env]["port"].to_s if abcs[Rails.env]['port']
-        ENV['PGPASSWORD'] = abcs[Rails.env]['password'].to_s if abcs[Rails.env]['password']
+        set_psql_env(abcs[Rails.env])
         search_path = abcs[Rails.env]['schema_search_path']
         unless search_path.blank?
           search_path = search_path.split(",").map{|search_path_part| "--schema=#{search_path_part.strip}" }.join(" ")
         end
-        `pg_dump -i -U "#{abcs[Rails.env]['username']}" -s -x -O -f db/#{Rails.env}_structure.sql #{search_path} #{abcs[Rails.env]['database']}`
+        `pg_dump -i -s -x -O -f #{filename} #{search_path} #{abcs[Rails.env]['database']}`
         raise 'Error dumping database' if $?.exitstatus == 1
       when /sqlite/
-        dbfile = abcs[Rails.env]['database'] || abcs[Rails.env]['dbfile']
-        `sqlite3 #{dbfile} .schema > db/#{Rails.env}_structure.sql`
+        dbfile = abcs[Rails.env]['database']
+        `sqlite3 #{dbfile} .schema > #{filename}`
       when 'sqlserver'
-        `smoscript -s #{abcs[Rails.env]['host']} -d #{abcs[Rails.env]['database']} -u #{abcs[Rails.env]['username']} -p #{abcs[Rails.env]['password']} -f db\\#{Rails.env}_structure.sql -A -U`
+        `smoscript -s #{abcs[Rails.env]['host']} -d #{abcs[Rails.env]['database']} -u #{abcs[Rails.env]['username']} -p #{abcs[Rails.env]['password']} -f #{filename} -A -U`
       when "firebird"
         set_firebird_env(abcs[Rails.env])
         db_string = firebird_db_string(abcs[Rails.env])
-        sh "isql -a #{db_string} > #{Rails.root}/db/#{Rails.env}_structure.sql"
+        sh "isql -a #{db_string} > #{filename}"
       else
         raise "Task not supported by '#{abcs[Rails.env]["adapter"]}'"
       end
 
       if ActiveRecord::Base.connection.supports_migrations?
-        File.open("#{Rails.root}/db/#{Rails.env}_structure.sql", "a") { |f| f << ActiveRecord::Base.connection.dump_schema_information }
+        File.open(filename, "a") { |f| f << ActiveRecord::Base.connection.dump_schema_information }
       end
     end
-  end
-
-  namespace :test do
-    # desc "Recreate the test database from the current schema.rb"
-    task :load => 'db:test:purge' do
-      ActiveRecord::Base.establish_connection(ActiveRecord::Base.configurations['test'])
-      ActiveRecord::Schema.verbose = false
-      db_namespace['schema:load'].invoke
-    end
 
-    # desc "Recreate the test database from the current environment's database schema"
-    task :clone => %w(db:schema:dump db:test:load)
+    # desc "Recreate the databases from the structure.sql file"
+    task :load => [:environment, :load_config] do
+      env = ENV['RAILS_ENV'] || 'test'
 
-    # desc "Recreate the test databases from the development structure"
-    task :clone_structure => [ 'db:structure:dump', 'db:test:purge' ] do
       abcs = ActiveRecord::Base.configurations
-      case abcs['test']['adapter']
+      filename = ENV['DB_STRUCTURE'] || File.join(Rails.root, "db", "structure.sql")
+      case abcs[env]['adapter']
       when /mysql/
-        ActiveRecord::Base.establish_connection(:test)
+        ActiveRecord::Base.establish_connection(abcs[env])
         ActiveRecord::Base.connection.execute('SET foreign_key_checks = 0')
-        IO.readlines("#{Rails.root}/db/#{Rails.env}_structure.sql").join.split("\n\n").each do |table|
+        IO.read(filename).split("\n\n").each do |table|
           ActiveRecord::Base.connection.execute(table)
         end
       when /postgresql/
-        ENV['PGHOST']     = abcs['test']['host'] if abcs['test']['host']
-        ENV['PGPORT']     = abcs['test']['port'].to_s if abcs['test']['port']
-        ENV['PGPASSWORD'] = abcs['test']['password'].to_s if abcs['test']['password']
-        `psql -U "#{abcs['test']['username']}" -f #{Rails.root}/db/#{Rails.env}_structure.sql #{abcs['test']['database']} #{abcs['test']['template']}`
+        set_psql_env(abcs[env])
+        `psql -f "#{filename}" #{abcs[env]['database']} #{abcs[env]['template']}`
       when /sqlite/
-        dbfile = abcs['test']['database'] || abcs['test']['dbfile']
-        `sqlite3 #{dbfile} < #{Rails.root}/db/#{Rails.env}_structure.sql`
+        dbfile = abcs[env]['database']
+        `sqlite3 #{dbfile} < "#{filename}"`
       when 'sqlserver'
-        `sqlcmd -S #{abcs['test']['host']} -d #{abcs['test']['database']} -U #{abcs['test']['username']} -P #{abcs['test']['password']} -i db\\#{Rails.env}_structure.sql`
+        `sqlcmd -S #{abcs[env]['host']} -d #{abcs[env]['database']} -U #{abcs[env]['username']} -P #{abcs[env]['password']} -i #{filename}`
       when 'oci', 'oracle'
-        ActiveRecord::Base.establish_connection(:test)
-        IO.readlines("#{Rails.root}/db/#{Rails.env}_structure.sql").join.split(";\n\n").each do |ddl|
+        ActiveRecord::Base.establish_connection(abcs[env])
+        IO.read(filename).split(";\n\n").each do |ddl|
           ActiveRecord::Base.connection.execute(ddl)
         end
       when 'firebird'
-        set_firebird_env(abcs['test'])
-        db_string = firebird_db_string(abcs['test'])
-        sh "isql -i #{Rails.root}/db/#{Rails.env}_structure.sql #{db_string}"
+        set_firebird_env(abcs[env])
+        db_string = firebird_db_string(abcs[env])
+        sh "isql -i #{filename} #{db_string}"
       else
-        raise "Task not supported by '#{abcs['test']['adapter']}'"
+        raise "Task not supported by '#{abcs[env]['adapter']}'"
       end
     end
 
+    task :load_if_sql => 'db:create' do
+      db_namespace["structure:load"].invoke if ActiveRecord::Base.schema_format == :sql
+    end
+  end
+
+  namespace :test do
+
+    # desc "Recreate the test database from the current schema"
+    task :load => 'db:test:purge' do
+      case ActiveRecord::Base.schema_format
+        when :ruby
+          db_namespace["test:load_schema"].invoke
+        when :sql
+          db_namespace["test:load_structure"].invoke
+        end
+    end
+
+    # desc "Recreate the test database from an existent structure.sql file"
+    task :load_structure => 'db:test:purge' do
+      begin
+        old_env, ENV['RAILS_ENV'] = ENV['RAILS_ENV'], 'test'
+        db_namespace["structure:load"].invoke
+      ensure
+        ENV['RAILS_ENV'] = old_env
+      end
+    end
+
+    # desc "Recreate the test database from an existent schema.rb file"
+    task :load_schema => 'db:test:purge' do
+      ActiveRecord::Base.establish_connection(ActiveRecord::Base.configurations['test'])
+      ActiveRecord::Schema.verbose = false
+      db_namespace["schema:load"].invoke
+    end
+
+    # desc "Recreate the test database from a fresh schema.rb file"
+    task :clone => %w(db:schema:dump db:test:load_schema)
+
+    # desc "Recreate the test database from a fresh structure.sql file"
+    task :clone_structure => [ "db:structure:dump", "db:test:load_structure" ]
+
     # desc "Empty the test database"
     task :purge => :environment do
       abcs = ActiveRecord::Base.configurations
@@ -456,7 +492,7 @@ db_namespace = namespace :db do
         drop_database(abcs['test'])
         create_database(abcs['test'])
       when /sqlite/
-        dbfile = abcs['test']['database'] || abcs['test']['dbfile']
+        dbfile = abcs['test']['database']
         File.delete(dbfile) if File.exist?(dbfile)
       when 'sqlserver'
         test = abcs.deep_dup['test']
@@ -479,7 +515,7 @@ db_namespace = namespace :db do
 
     # desc 'Check for pending migrations and load the test schema'
     task :prepare => 'db:abort_if_pending_migrations' do
-      if defined?(ActiveRecord) && !ActiveRecord::Base.configurations.blank?
+      unless ActiveRecord::Base.configurations.blank?
         db_namespace[{ :sql  => 'test:clone_structure', :ruby => 'test:load' }[ActiveRecord::Base.schema_format]].invoke
       end
     end
@@ -548,6 +584,20 @@ def drop_database(config)
   end
 end
 
+def drop_database_and_rescue(config)
+  begin
+    drop_database(config)
+  rescue Exception => e
+    $stderr.puts "Couldn't drop #{config['database']} : #{e.inspect}"
+  end
+end
+
+def configs_for_environment
+  environments = [Rails.env]
+  environments << 'test' if Rails.env.development?
+  ActiveRecord::Base.configurations.values_at(*environments).compact.reject { |config| config['database'].blank? }
+end
+
 def session_table_name
   ActiveRecord::SessionStore::Session.table_name
 end
@@ -560,3 +610,10 @@ end
 def firebird_db_string(config)
   FireRuby::Database.db_string_for(config.symbolize_keys)
 end
+
+def set_psql_env(config)
+  ENV['PGHOST']     = config['host']          if config['host'] 
+  ENV['PGPORT']     = config['port'].to_s     if config['port']
+  ENV['PGPASSWORD'] = config['password'].to_s if config['password']
+  ENV['PGUSER']     = config['username'].to_s if config['username']
+end
diff --git a/activerecord/lib/active_record/readonly_attributes.rb b/activerecord/lib/active_record/readonly_attributes.rb
new file mode 100644
index 0000000000..836b15e2ce
--- /dev/null
+++ b/activerecord/lib/active_record/readonly_attributes.rb
@@ -0,0 +1,26 @@
+require 'active_support/concern'
+require 'active_support/core_ext/class/attribute'
+
+module ActiveRecord
+  module ReadonlyAttributes
+    extend ActiveSupport::Concern
+
+    included do
+      config_attribute :_attr_readonly
+      self._attr_readonly = []
+    end
+
+    module ClassMethods
+      # Attributes listed as readonly will be used to create a new record but update operations will
+      # ignore these fields.
+      def attr_readonly(*attributes)
+        self._attr_readonly = Set.new(attributes.map { |a| a.to_s }) + (self._attr_readonly || [])
+      end
+
+      # Returns an array of all the attributes that have been specified as readonly.
+      def readonly_attributes
+        self._attr_readonly
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb
index 120ff0cac6..60b73e9fe5 100644
--- a/activerecord/lib/active_record/reflection.rb
+++ b/activerecord/lib/active_record/reflection.rb
@@ -7,7 +7,8 @@ module ActiveRecord
     extend ActiveSupport::Concern
 
     included do
-      class_attribute :reflections
+      extend ActiveModel::Configuration
+      config_attribute :reflections
       self.reflections = {}
     end
 
@@ -124,7 +125,7 @@ module ActiveRecord
       # <tt>composed_of :balance, :class_name => 'Money'</tt> returns <tt>'Money'</tt>
       # <tt>has_many :clients</tt> returns <tt>'Client'</tt>
       def class_name
-        @class_name ||= options[:class_name] || derive_class_name
+        @class_name ||= (options[:class_name] || derive_class_name).to_s
       end
 
       # Returns +true+ if +self+ and +other_aggregation+ have the same +name+ attribute, +active_record+ attribute,
@@ -213,11 +214,11 @@ module ActiveRecord
 
       # klass option is necessary to support loading polymorphic associations
       def association_primary_key(klass = nil)
-        options[:primary_key] || (klass || self.klass).primary_key
+        options[:primary_key] || primary_key(klass || self.klass)
       end
 
       def active_record_primary_key
-        @active_record_primary_key ||= options[:primary_key] || active_record.primary_key
+        @active_record_primary_key ||= options[:primary_key] || primary_key(active_record)
       end
 
       def counter_cache_column
@@ -262,6 +263,10 @@ module ActiveRecord
         [self]
       end
 
+      def nested?
+        false
+      end
+
       # An array of arrays of conditions. Each item in the outside array corresponds to a reflection
       # in the #chain. The inside arrays are simply conditions (and each condition may itself be
       # a hash, array, arel predicate, etc...)
@@ -357,6 +362,10 @@ module ActiveRecord
             active_record.name.foreign_key
           end
         end
+
+        def primary_key(klass)
+          klass.primary_key || raise(UnknownPrimaryKey.new(klass))
+        end
     end
 
     # Holds all the meta-data about a :through association as it was specified
@@ -429,7 +438,7 @@ module ActiveRecord
       # of relevant reflections, plus any :source_type or polymorphic :as constraints.
       def conditions
         @conditions ||= begin
-          conditions = source_reflection.conditions
+          conditions = source_reflection.conditions.map { |c| c.dup }
 
           # Add to it the conditions from this reflection if necessary.
           conditions.first << options[:conditions] if options[:conditions]
@@ -453,7 +462,7 @@ module ActiveRecord
         source_reflection.source_macro
       end
 
-      # A through association is nested iff there would be more than one join table
+      # A through association is nested if there would be more than one join table
       def nested?
         chain.length > 2 || through_reflection.macro == :has_and_belongs_to_many
       end
@@ -461,7 +470,7 @@ module ActiveRecord
       # We want to use the klass from this reflection, rather than just delegate straight to
       # the source_reflection, because the source_reflection may be polymorphic. We still
       # need to respect the source_reflection's :primary_key option, though.
-      def association_primary_key(klass = self.klass)
+      def association_primary_key(klass = nil)
         # Get the "actual" source reflection if the immediate source reflection has a
         # source reflection itself
         source_reflection = self.source_reflection
@@ -469,7 +478,7 @@ module ActiveRecord
           source_reflection = source_reflection.source_reflection
         end
 
-        source_reflection.options[:primary_key] || klass.primary_key
+        source_reflection.options[:primary_key] || primary_key(klass || self.klass)
       end
 
       # Gets an array of possible <tt>:through</tt> source reflection names:
diff --git a/activerecord/lib/active_record/relation.rb b/activerecord/lib/active_record/relation.rb
index bf61d79a2c..6f2248fa21 100644
--- a/activerecord/lib/active_record/relation.rb
+++ b/activerecord/lib/active_record/relation.rb
@@ -1,5 +1,6 @@
+# -*- coding: utf-8 -*-
 require 'active_support/core_ext/object/blank'
-require 'active_support/core_ext/module/delegation'
+require 'active_support/deprecation'
 
 module ActiveRecord
   # = Active Record Relation
@@ -7,13 +8,9 @@ module ActiveRecord
     JoinOperation = Struct.new(:relation, :join_class, :on)
     ASSOCIATION_METHODS = [:includes, :eager_load, :preload]
     MULTI_VALUE_METHODS = [:select, :group, :order, :joins, :where, :having, :bind]
-    SINGLE_VALUE_METHODS = [:limit, :offset, :lock, :readonly, :from, :reorder, :reverse_order]
+    SINGLE_VALUE_METHODS = [:limit, :offset, :lock, :readonly, :from, :reorder, :reverse_order, :uniq]
 
-    include FinderMethods, Calculations, SpawnMethods, QueryMethods, Batches
-
-    # These are explicitly delegated to improve performance (avoids method_missing)
-    delegate :to_xml, :to_yaml, :length, :collect, :map, :each, :all?, :include?, :to => :to_a
-    delegate :table_name, :quoted_table_name, :primary_key, :primary_key?, :quoted_primary_key, :connection, :column_hash,:to => :klass
+    include FinderMethods, Calculations, SpawnMethods, QueryMethods, Batches, Explain, Delegation
 
     attr_reader :table, :klass, :loaded
     attr_accessor :extensions, :default_scoped
@@ -36,7 +33,7 @@ module ActiveRecord
     def insert(values)
       primary_key_value = nil
 
-      if primary_key? && Hash === values
+      if primary_key && Hash === values
         primary_key_value = values[values.keys.find { |k|
           k.name == primary_key
         }]
@@ -70,7 +67,7 @@ module ActiveRecord
       conn.insert(
         im,
         'SQL',
-        primary_key? && primary_key,
+        primary_key,
         primary_key_value,
         nil,
         binds)
@@ -136,14 +133,35 @@ module ActiveRecord
       first || new(attributes, options, &block)
     end
 
-    def respond_to?(method, include_private = false)
-      arel.respond_to?(method, include_private)     ||
-        Array.method_defined?(method)               ||
-        @klass.respond_to?(method, include_private) ||
-        super
+    # Runs EXPLAIN on the query or queries triggered by this relation and
+    # returns the result as a string. The string is formatted imitating the
+    # ones printed by the database shell.
+    #
+    # Note that this method actually runs the queries, since the results of some
+    # are needed by the next ones when eager loading is going on.
+    #
+    # Please see further details in the
+    # {Active Record Query Interface guide}[http://edgeguides.rubyonrails.org/active_record_querying.html#running-explain].
+    def explain
+      _, queries = collecting_queries_for_explain { exec_queries }
+      exec_explain(queries)
     end
 
     def to_a
+      # We monitor here the entire execution rather than individual SELECTs
+      # because from the point of view of the user fetching the records of a
+      # relation is a single unit of work. You want to know if this call takes
+      # too long, not if the individual queries take too long.
+      #
+      # It could be the case that none of the queries involved surpass the
+      # threshold, and at the same time the sum of them all does. The user
+      # should get a query plan logged in that case.
+      logging_query_plan do
+        exec_queries
+      end
+    end
+
+    def exec_queries
       return @records if loaded?
 
       default_scoped = with_default_scope
@@ -174,6 +192,7 @@ module ActiveRecord
       @loaded = true
       @records
     end
+    private :exec_queries
 
     def as_json(options = nil) #:nodoc:
       to_a.as_json(options)
@@ -219,7 +238,7 @@ module ActiveRecord
     # Please check unscoped if you want to remove all previous scopes (including
     # the default_scope) during the execution of a block.
     def scoping
-      @klass.send(:with_scope, self, :overwrite) { yield }
+      @klass.with_scope(self, :overwrite) { yield }
     end
 
     # Updates all records with details given if they match a set of conditions supplied, limits and order can
@@ -337,7 +356,7 @@ module ActiveRecord
       end
     end
 
-    # Destroy an object (or multiple objects) that has the given id, the object is instantiated first,
+    # Destroy an object (or multiple objects) that has the given id. The object is instantiated first,
     # therefore all callbacks and filters are fired off before the object is deleted. This method is
     # less efficient than ActiveRecord#delete but allows cleanup methods and other actions to be run.
     #
@@ -487,20 +506,6 @@ module ActiveRecord
       end
     end
 
-    protected
-
-    def method_missing(method, *args, &block)
-      if Array.method_defined?(method)
-        to_a.send(method, *args, &block)
-      elsif @klass.respond_to?(method)
-        scoping { @klass.send(method, *args, &block) }
-      elsif arel.respond_to?(method)
-        arel.send(method, *args, &block)
-      else
-        super
-      end
-    end
-
     private
 
     def references_eager_loaded_tables?
@@ -517,7 +522,18 @@ module ActiveRecord
       # always convert table names to downcase as in Oracle quoted table names are in uppercase
       joined_tables = joined_tables.flatten.compact.map { |t| t.downcase }.uniq
 
-      (tables_in_string(to_sql) - joined_tables).any?
+      referenced_tables = (tables_in_string(to_sql) - joined_tables)
+      if referenced_tables.any?
+        ActiveSupport::Deprecation.warn(
+          "Your query appears to reference tables (#{referenced_tables.join(', ')}) that are not " \
+          "explicitly joined. This implicit joining is deprecated, so you must explicitly " \
+          "reference the tables. For example, instead of Author.includes(:posts).where(\"posts.name = 'foo'\"), " \
+          "you should write Author.eager_load(:posts).where(\"posts.name = 'foo'\")."
+        )
+        true
+      else
+        false
+      end
     end
 
     def tables_in_string(string)
@@ -526,6 +542,5 @@ module ActiveRecord
       # ignore raw_sql_ that is used by Oracle adapter as alias for limit/offset subqueries
       string.scan(/([a-zA-Z_][.\w]+).?\./).flatten.map{ |s| s.downcase }.uniq - ['raw_sql_']
     end
-
   end
 end
diff --git a/activerecord/lib/active_record/relation/calculations.rb b/activerecord/lib/active_record/relation/calculations.rb
index af86771d2d..bf9b4bf1c9 100644
--- a/activerecord/lib/active_record/relation/calculations.rb
+++ b/activerecord/lib/active_record/relation/calculations.rb
@@ -166,6 +166,22 @@ module ActiveRecord
       0
     end
 
+    # This method is designed to perform select by a single column as direct SQL query
+    # Returns <tt>Array</tt> with values of the specified column name
+    # The values has same data type as column.
+    #
+    # Examples:
+    #
+    #   Person.pluck(:id) # SELECT people.id FROM people
+    #   Person.uniq.pluck(:role) # SELECT DISTINCT role FROM people
+    #   Person.where(:confirmed => true).limit(5).pluck(:id)
+    #
+    def pluck(column_name)
+      klass.connection.select_all(select(column_name).arel).map! do |attributes|
+        klass.type_cast_attribute(attributes.keys.first, klass.initialize_attributes(attributes))
+      end
+    end
+
     private
 
     def perform_calculation(operation, column_name, options = {})
diff --git a/activerecord/lib/active_record/relation/delegation.rb b/activerecord/lib/active_record/relation/delegation.rb
new file mode 100644
index 0000000000..f5fdf437bf
--- /dev/null
+++ b/activerecord/lib/active_record/relation/delegation.rb
@@ -0,0 +1,49 @@
+require 'active_support/core_ext/module/delegation'
+
+module ActiveRecord
+  module Delegation
+    # Set up common delegations for performance (avoids method_missing)
+    delegate :to_xml, :to_yaml, :length, :collect, :map, :each, :all?, :include?, :to_ary, :to => :to_a
+    delegate :table_name, :quoted_table_name, :primary_key, :quoted_primary_key,
+             :connection, :columns_hash, :auto_explain_threshold_in_seconds, :to => :klass
+
+    def self.delegate_to_scoped_klass(method)
+      if method.to_s =~ /\A[a-zA-Z_]\w*[!?]?\z/
+        module_eval <<-RUBY, __FILE__, __LINE__ + 1
+          def #{method}(*args, &block)
+            scoping { @klass.#{method}(*args, &block) }
+          end
+        RUBY
+      else
+        module_eval <<-RUBY, __FILE__, __LINE__ + 1
+          def #{method}(*args, &block)
+            scoping { @klass.send(#{method.inspect}, *args, &block) }
+          end
+        RUBY
+      end
+    end
+
+    def respond_to?(method, include_private = false)
+      super || Array.method_defined?(method) ||
+        @klass.respond_to?(method, include_private) ||
+        arel.respond_to?(method, include_private)
+    end
+
+    protected
+
+    def method_missing(method, *args, &block)
+      if Array.method_defined?(method)
+        ::ActiveRecord::Delegation.delegate method, :to => :to_a
+        to_a.send(method, *args, &block)
+      elsif @klass.respond_to?(method)
+        ::ActiveRecord::Delegation.delegate_to_scoped_klass(method)
+        scoping { @klass.send(method, *args, &block) }
+      elsif arel.respond_to?(method)
+        ::ActiveRecord::Delegation.delegate method, :to => :arel
+        arel.send(method, *args, &block)
+      else
+        super
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/activerecord/lib/active_record/relation/finder_methods.rb b/activerecord/lib/active_record/relation/finder_methods.rb
index 7eeb3dde70..e58c726e09 100644
--- a/activerecord/lib/active_record/relation/finder_methods.rb
+++ b/activerecord/lib/active_record/relation/finder_methods.rb
@@ -187,11 +187,11 @@ module ActiveRecord
     def exists?(id = false)
       return false if id.nil?
 
-      id = id.id if ActiveRecord::Base === id
+      id = id.id if ActiveRecord::Model === id
 
       join_dependency = construct_join_dependency_for_association_find
       relation = construct_relation_for_association_find(join_dependency)
-      relation = relation.except(:select).select("1").limit(1)
+      relation = relation.except(:select, :order).select("1").limit(1)
 
       case id
       when Array, Hash
@@ -249,7 +249,7 @@ module ActiveRecord
     end
 
     def construct_limited_ids_condition(relation)
-      orders = relation.order_values.map { |val| val.presence }.compact
+      orders = (relation.reorder_value || relation.order_values).map { |val| val.presence }.compact
       values = @klass.connection.distinct("#{@klass.connection.quote_table_name table_name}.#{primary_key}", orders)
 
       relation = relation.dup
diff --git a/activerecord/lib/active_record/relation/predicate_builder.rb b/activerecord/lib/active_record/relation/predicate_builder.rb
index 7e8ddd1b5d..88081edae2 100644
--- a/activerecord/lib/active_record/relation/predicate_builder.rb
+++ b/activerecord/lib/active_record/relation/predicate_builder.rb
@@ -15,42 +15,49 @@ module ActiveRecord
             table = Arel::Table.new(table_name, engine)
           end
 
-          attribute = table[column.to_sym]
+          build(table[column.to_sym], value)
+        end
+      end
+      predicates.flatten
+    end
+
+    private
+      def self.build(attribute, value)
+        case value
+        when ActiveRecord::Relation
+          value = value.select(value.klass.arel_table[value.klass.primary_key]) if value.select_values.empty?
+          attribute.in(value.arel.ast)
+        when Array, ActiveRecord::Associations::CollectionProxy
+          values = value.to_a.map {|x| x.is_a?(ActiveRecord::Model) ? x.id : x}
+          ranges, values = values.partition {|v| v.is_a?(Range) || v.is_a?(Arel::Relation)}
 
-          case value
-          when ActiveRecord::Relation
-            value = value.select(value.klass.arel_table[value.klass.primary_key]) if value.select_values.empty?
-            attribute.in(value.arel.ast)
-          when Array, ActiveRecord::Associations::CollectionProxy
-            values = value.to_a.map { |x|
-              x.is_a?(ActiveRecord::Base) ? x.id : x
-            }
+          array_predicates = ranges.map {|range| attribute.in(range)}
 
-            if values.include?(nil)
-              values = values.compact
-              if values.empty?
-                attribute.eq nil
-              else
-                attribute.in(values.compact).or attribute.eq(nil)
-              end
+          if values.include?(nil)
+            values = values.compact
+            case values.length
+            when 0
+              array_predicates << attribute.eq(nil)
+            when 1
+              array_predicates << attribute.eq(values.first).or(attribute.eq(nil))
             else
-              attribute.in(values)
+              array_predicates << attribute.in(values).or(attribute.eq(nil))
             end
-
-          when Range, Arel::Relation
-            attribute.in(value)
-          when ActiveRecord::Base
-            attribute.eq(value.id)
-          when Class
-            # FIXME: I think we need to deprecate this behavior
-            attribute.eq(value.name)
           else
-            attribute.eq(value)
+            array_predicates << attribute.in(values)
           end
+
+          array_predicates.inject {|composite, predicate| composite.or(predicate)}
+        when Range, Arel::Relation
+          attribute.in(value)
+        when ActiveRecord::Model
+          attribute.eq(value.id)
+        when Class
+          # FIXME: I think we need to deprecate this behavior
+          attribute.eq(value.name)
+        else
+          attribute.eq(value)
         end
       end
-
-      predicates.flatten
-    end
   end
 end
diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb
index 670ba0987d..c281bead0d 100644
--- a/activerecord/lib/active_record/relation/query_methods.rb
+++ b/activerecord/lib/active_record/relation/query_methods.rb
@@ -9,7 +9,8 @@ module ActiveRecord
                   :select_values, :group_values, :order_values, :joins_values,
                   :where_values, :having_values, :bind_values,
                   :limit_value, :offset_value, :lock_value, :readonly_value, :create_with_value,
-                  :from_value, :reorder_value, :reverse_order_value
+                  :from_value, :reorder_value, :reverse_order_value,
+                  :uniq_value
 
     def includes(*args)
       args.reject! {|a| a.blank? }
@@ -38,7 +39,7 @@ module ActiveRecord
     end
 
     # Works in two unique ways.
-    # 
+    #
     # First: takes a block so it can be used just like Array#select.
     #
     #   Model.scoped.select { |m| m.field == value }
@@ -176,9 +177,25 @@ module ActiveRecord
       relation
     end
 
+    # Specifies whether the records should be unique or not. For example:
+    #
+    #   User.select(:name)
+    #   # => Might return two records with the same name
+    #
+    #   User.select(:name).uniq
+    #   # => Returns 1 record per unique name
+    #
+    #   User.select(:name).uniq.uniq(false)
+    #   # => You can also remove the uniqueness
+    def uniq(value = true)
+      relation = clone
+      relation.uniq_value = value
+      relation
+    end
+
     # Used to extend a scope with additional methods, either through
-    # a module or through a block provided. 
-    # 
+    # a module or through a block provided.
+    #
     # The object returned is a relation, which can be further extended.
     #
     # === Using a module
@@ -200,7 +217,7 @@ module ActiveRecord
     #
     #   scope = Model.scoped.extending do
     #     def page(number)
-    #       # pagination code goes here 
+    #       # pagination code goes here
     #     end
     #   end
     #   scope.page(params[:page])
@@ -209,7 +226,7 @@ module ActiveRecord
     #
     #   scope = Model.scoped.extending(Pagination) do
     #     def per_page(number)
-    #       # pagination code goes here 
+    #       # pagination code goes here
     #     end
     #   end
     def extending(*modules)
@@ -252,6 +269,7 @@ module ActiveRecord
 
       build_select(arel, @select_values.uniq)
 
+      arel.distinct(@uniq_value)
       arel.from(@from_value) if @from_value
       arel.lock(@lock_value) if @lock_value
 
diff --git a/activerecord/lib/active_record/relation/spawn_methods.rb b/activerecord/lib/active_record/relation/spawn_methods.rb
index ba882beca9..a5194beae5 100644
--- a/activerecord/lib/active_record/relation/spawn_methods.rb
+++ b/activerecord/lib/active_record/relation/spawn_methods.rb
@@ -113,7 +113,7 @@ module ActiveRecord
       result
     end
 
-    VALID_FIND_OPTIONS = [ :conditions, :include, :joins, :limit, :offset, :extend,
+    VALID_FIND_OPTIONS = [ :conditions, :include, :joins, :limit, :offset, :extend, :eager_load,
                            :order, :select, :readonly, :group, :having, :from, :lock ]
 
     def apply_finder_options(options)
@@ -124,7 +124,7 @@ module ActiveRecord
       finders = options.dup
       finders.delete_if { |key, value| value.nil? && key != :limit }
 
-      ([:joins, :select, :group, :order, :having, :limit, :offset, :from, :lock, :readonly] & finders.keys).each do |finder|
+      ([:joins, :select, :group, :order, :having, :limit, :offset, :from, :lock, :readonly, :eager_load] & finders.keys).each do |finder|
         relation = relation.send(finder, finders[finder])
       end
 
diff --git a/activerecord/lib/active_record/sanitization.rb b/activerecord/lib/active_record/sanitization.rb
new file mode 100644
index 0000000000..2d7d83d160
--- /dev/null
+++ b/activerecord/lib/active_record/sanitization.rb
@@ -0,0 +1,194 @@
+require 'active_support/concern'
+
+module ActiveRecord
+  module Sanitization
+    extend ActiveSupport::Concern
+
+    module ClassMethods
+      def quote_value(value, column = nil) #:nodoc:
+        connection.quote(value,column)
+      end
+
+      # Used to sanitize objects before they're used in an SQL SELECT statement. Delegates to <tt>connection.quote</tt>.
+      def sanitize(object) #:nodoc:
+        connection.quote(object)
+      end
+
+      protected
+
+      # Accepts an array, hash, or string of SQL conditions and sanitizes
+      # them into a valid SQL fragment for a WHERE clause.
+      #   ["name='%s' and group_id='%s'", "foo'bar", 4]  returns  "name='foo''bar' and group_id='4'"
+      #   { :name => "foo'bar", :group_id => 4 }  returns "name='foo''bar' and group_id='4'"
+      #   "name='foo''bar' and group_id='4'" returns "name='foo''bar' and group_id='4'"
+      def sanitize_sql_for_conditions(condition, table_name = self.table_name)
+        return nil if condition.blank?
+
+        case condition
+        when Array; sanitize_sql_array(condition)
+        when Hash;  sanitize_sql_hash_for_conditions(condition, table_name)
+        else        condition
+        end
+      end
+      alias_method :sanitize_sql, :sanitize_sql_for_conditions
+
+      # Accepts an array, hash, or string of SQL conditions and sanitizes
+      # them into a valid SQL fragment for a SET clause.
+      #   { :name => nil, :group_id => 4 }  returns "name = NULL , group_id='4'"
+      def sanitize_sql_for_assignment(assignments)
+        case assignments
+          when Array; sanitize_sql_array(assignments)
+          when Hash;  sanitize_sql_hash_for_assignment(assignments)
+          else        assignments
+        end
+      end
+
+      # Accepts a hash of SQL conditions and replaces those attributes
+      # that correspond to a +composed_of+ relationship with their expanded
+      # aggregate attribute values.
+      # Given:
+      #     class Person < ActiveRecord::Base
+      #       composed_of :address, :class_name => "Address",
+      #         :mapping => [%w(address_street street), %w(address_city city)]
+      #     end
+      # Then:
+      #     { :address => Address.new("813 abc st.", "chicago") }
+      #       # => { :address_street => "813 abc st.", :address_city => "chicago" }
+      def expand_hash_conditions_for_aggregates(attrs)
+        expanded_attrs = {}
+        attrs.each do |attr, value|
+          unless (aggregation = reflect_on_aggregation(attr.to_sym)).nil?
+            mapping = aggregate_mapping(aggregation)
+            mapping.each do |field_attr, aggregate_attr|
+              if mapping.size == 1 && !value.respond_to?(aggregate_attr)
+                expanded_attrs[field_attr] = value
+              else
+                expanded_attrs[field_attr] = value.send(aggregate_attr)
+              end
+            end
+          else
+            expanded_attrs[attr] = value
+          end
+        end
+        expanded_attrs
+      end
+
+      # Sanitizes a hash of attribute/value pairs into SQL conditions for a WHERE clause.
+      #   { :name => "foo'bar", :group_id => 4 }
+      #     # => "name='foo''bar' and group_id= 4"
+      #   { :status => nil, :group_id => [1,2,3] }
+      #     # => "status IS NULL and group_id IN (1,2,3)"
+      #   { :age => 13..18 }
+      #     # => "age BETWEEN 13 AND 18"
+      #   { 'other_records.id' => 7 }
+      #     # => "`other_records`.`id` = 7"
+      #   { :other_records => { :id => 7 } }
+      #     # => "`other_records`.`id` = 7"
+      # And for value objects on a composed_of relationship:
+      #   { :address => Address.new("123 abc st.", "chicago") }
+      #     # => "address_street='123 abc st.' and address_city='chicago'"
+      def sanitize_sql_hash_for_conditions(attrs, default_table_name = self.table_name)
+        attrs = expand_hash_conditions_for_aggregates(attrs)
+
+        table = Arel::Table.new(table_name).alias(default_table_name)
+        PredicateBuilder.build_from_hash(arel_engine, attrs, table).map { |b|
+          connection.visitor.accept b
+        }.join(' AND ')
+      end
+      alias_method :sanitize_sql_hash, :sanitize_sql_hash_for_conditions
+
+      # Sanitizes a hash of attribute/value pairs into SQL conditions for a SET clause.
+      #   { :status => nil, :group_id => 1 }
+      #     # => "status = NULL , group_id = 1"
+      def sanitize_sql_hash_for_assignment(attrs)
+        attrs.map do |attr, value|
+          "#{connection.quote_column_name(attr)} = #{quote_bound_value(value)}"
+        end.join(', ')
+      end
+
+      # Accepts an array of conditions. The array has each value
+      # sanitized and interpolated into the SQL statement.
+      #   ["name='%s' and group_id='%s'", "foo'bar", 4]  returns  "name='foo''bar' and group_id='4'"
+      def sanitize_sql_array(ary)
+        statement, *values = ary
+        if values.first.is_a?(Hash) && statement =~ /:\w+/
+          replace_named_bind_variables(statement, values.first)
+        elsif statement.include?('?')
+          replace_bind_variables(statement, values)
+        elsif statement.blank?
+          statement
+        else
+          statement % values.collect { |value| connection.quote_string(value.to_s) }
+        end
+      end
+
+      alias_method :sanitize_conditions, :sanitize_sql
+
+      def replace_bind_variables(statement, values) #:nodoc:
+        raise_if_bind_arity_mismatch(statement, statement.count('?'), values.size)
+        bound = values.dup
+        c = connection
+        statement.gsub('?') { quote_bound_value(bound.shift, c) }
+      end
+
+      def replace_named_bind_variables(statement, bind_vars) #:nodoc:
+        statement.gsub(/(:?):([a-zA-Z]\w*)/) do
+          if $1 == ':' # skip postgresql casts
+            $& # return the whole match
+          elsif bind_vars.include?(match = $2.to_sym)
+            quote_bound_value(bind_vars[match])
+          else
+            raise PreparedStatementInvalid, "missing value for :#{match} in #{statement}"
+          end
+        end
+      end
+
+      def expand_range_bind_variables(bind_vars) #:nodoc:
+        expanded = []
+
+        bind_vars.each do |var|
+          next if var.is_a?(Hash)
+
+          if var.is_a?(Range)
+            expanded << var.first
+            expanded << var.last
+          else
+            expanded << var
+          end
+        end
+
+        expanded
+      end
+
+      def quote_bound_value(value, c = connection) #:nodoc:
+        if value.respond_to?(:map) && !value.acts_like?(:string)
+          if value.respond_to?(:empty?) && value.empty?
+            c.quote(nil)
+          else
+            value.map { |v| c.quote(v) }.join(',')
+          end
+        else
+          c.quote(value)
+        end
+      end
+
+      def raise_if_bind_arity_mismatch(statement, expected, provided) #:nodoc:
+        unless expected == provided
+          raise PreparedStatementInvalid, "wrong number of bind variables (#{provided} for #{expected}) in: #{statement}"
+        end
+      end
+    end
+
+    # TODO: Deprecate this
+    def quoted_id #:nodoc:
+      quote_value(id, column_for_attribute(self.class.primary_key))
+    end
+
+    private
+
+    # Quote strings appropriately for SQL statements.
+    def quote_value(value, column = nil)
+      self.class.connection.quote(value, column)
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/schema_dumper.rb b/activerecord/lib/active_record/schema_dumper.rb
index 6fe305f843..cdde5cf3b9 100644
--- a/activerecord/lib/active_record/schema_dumper.rb
+++ b/activerecord/lib/active_record/schema_dumper.rb
@@ -190,6 +190,9 @@ HEADER
             index_lengths = (index.lengths || []).compact
             statement_parts << (':length => ' + Hash[index.columns.zip(index.lengths)].inspect) unless index_lengths.empty?
 
+            index_orders = (index.orders || {})
+            statement_parts << (':order => ' + index.orders.inspect) unless index_orders.empty?
+
             '  ' + statement_parts.join(', ')
           end
 
diff --git a/activerecord/lib/active_record/scoping.rb b/activerecord/lib/active_record/scoping.rb
new file mode 100644
index 0000000000..a8f5e96190
--- /dev/null
+++ b/activerecord/lib/active_record/scoping.rb
@@ -0,0 +1,152 @@
+require 'active_support/concern'
+
+module ActiveRecord
+  module Scoping
+    extend ActiveSupport::Concern
+
+    included do
+      include Default
+      include Named
+    end
+
+    module ClassMethods
+      # with_scope lets you apply options to inner block incrementally. It takes a hash and the keys must be
+      # <tt>:find</tt> or <tt>:create</tt>. <tt>:find</tt> parameter is <tt>Relation</tt> while
+      # <tt>:create</tt> parameters are an attributes hash.
+      #
+      #   class Article < ActiveRecord::Base
+      #     def self.create_with_scope
+      #       with_scope(:find => where(:blog_id => 1), :create => { :blog_id => 1 }) do
+      #         find(1) # => SELECT * from articles WHERE blog_id = 1 AND id = 1
+      #         a = create(1)
+      #         a.blog_id # => 1
+      #       end
+      #     end
+      #   end
+      #
+      # In nested scopings, all previous parameters are overwritten by the innermost rule, with the exception of
+      # <tt>where</tt>, <tt>includes</tt>, and <tt>joins</tt> operations in <tt>Relation</tt>, which are merged.
+      #
+      # <tt>joins</tt> operations are uniqued so multiple scopes can join in the same table without table aliasing
+      # problems. If you need to join multiple tables, but still want one of the tables to be uniqued, use the
+      # array of strings format for your joins.
+      #
+      #   class Article < ActiveRecord::Base
+      #     def self.find_with_scope
+      #       with_scope(:find => where(:blog_id => 1).limit(1), :create => { :blog_id => 1 }) do
+      #         with_scope(:find => limit(10)) do
+      #           all # => SELECT * from articles WHERE blog_id = 1 LIMIT 10
+      #         end
+      #         with_scope(:find => where(:author_id => 3)) do
+      #           all # => SELECT * from articles WHERE blog_id = 1 AND author_id = 3 LIMIT 1
+      #         end
+      #       end
+      #     end
+      #   end
+      #
+      # You can ignore any previous scopings by using the <tt>with_exclusive_scope</tt> method.
+      #
+      #   class Article < ActiveRecord::Base
+      #     def self.find_with_exclusive_scope
+      #       with_scope(:find => where(:blog_id => 1).limit(1)) do
+      #         with_exclusive_scope(:find => limit(10)) do
+      #           all # => SELECT * from articles LIMIT 10
+      #         end
+      #       end
+      #     end
+      #   end
+      #
+      # *Note*: the +:find+ scope also has effect on update and deletion methods, like +update_all+ and +delete_all+.
+      def with_scope(scope = {}, action = :merge, &block)
+        # If another Active Record class has been passed in, get its current scope
+        scope = scope.current_scope if !scope.is_a?(Relation) && scope.respond_to?(:current_scope)
+
+        previous_scope = self.current_scope
+
+        if scope.is_a?(Hash)
+          # Dup first and second level of hash (method and params).
+          scope = scope.dup
+          scope.each do |method, params|
+            scope[method] = params.dup unless params == true
+          end
+
+          scope.assert_valid_keys([ :find, :create ])
+          relation = construct_finder_arel(scope[:find] || {})
+          relation.default_scoped = true unless action == :overwrite
+
+          if previous_scope && previous_scope.create_with_value && scope[:create]
+            scope_for_create = if action == :merge
+              previous_scope.create_with_value.merge(scope[:create])
+            else
+              scope[:create]
+            end
+
+            relation = relation.create_with(scope_for_create)
+          else
+            scope_for_create = scope[:create]
+            scope_for_create ||= previous_scope.create_with_value if previous_scope
+            relation = relation.create_with(scope_for_create) if scope_for_create
+          end
+
+          scope = relation
+        end
+
+        scope = previous_scope.merge(scope) if previous_scope && action == :merge
+
+        self.current_scope = scope
+        begin
+          yield
+        ensure
+          self.current_scope = previous_scope
+        end
+      end
+
+      protected
+
+      # Works like with_scope, but discards any nested properties.
+      def with_exclusive_scope(method_scoping = {}, &block)
+        if method_scoping.values.any? { |e| e.is_a?(ActiveRecord::Relation) }
+          raise ArgumentError, <<-MSG
+  New finder API can not be used with_exclusive_scope. You can either call unscoped to get an anonymous scope not bound to the default_scope:
+
+  User.unscoped.where(:active => true)
+
+  Or call unscoped with a block:
+
+  User.unscoped do
+  User.where(:active => true).all
+  end
+
+  MSG
+        end
+        with_scope(method_scoping, :overwrite, &block)
+      end
+
+      def current_scope #:nodoc:
+        Thread.current["#{self}_current_scope"]
+      end
+
+      def current_scope=(scope) #:nodoc:
+        Thread.current["#{self}_current_scope"] = scope
+      end
+
+      private
+
+      def construct_finder_arel(options = {}, scope = nil)
+        relation = options.is_a?(Hash) ? unscoped.apply_finder_options(options) : options
+        relation = scope.merge(relation) if scope
+        relation
+      end
+
+    end
+
+    def populate_with_current_scope_attributes
+      return unless self.class.scope_attributes?
+
+      self.class.scope_attributes.each do |att,value|
+        send("#{att}=", value) if respond_to?("#{att}=")
+      end
+    end
+
+  end
+end
diff --git a/activerecord/lib/active_record/scoping/default.rb b/activerecord/lib/active_record/scoping/default.rb
new file mode 100644
index 0000000000..5f05d146f2
--- /dev/null
+++ b/activerecord/lib/active_record/scoping/default.rb
@@ -0,0 +1,142 @@
+require 'active_support/concern'
+
+module ActiveRecord
+  module Scoping
+    module Default
+      extend ActiveSupport::Concern
+
+      included do
+        # Stores the default scope for the class
+        config_attribute :default_scopes
+        self.default_scopes = []
+      end
+
+      module ClassMethods
+        # Returns a scope for the model without the default_scope.
+        #
+        #   class Post < ActiveRecord::Base
+        #     def self.default_scope
+        #       where :published => true
+        #     end
+        #   end
+        #
+        #   Post.all          # Fires "SELECT * FROM posts WHERE published = true"
+        #   Post.unscoped.all # Fires "SELECT * FROM posts"
+        #
+        # This method also accepts a block. All queries inside the block will
+        # not use the default_scope:
+        #
+        #   Post.unscoped {
+        #     Post.limit(10) # Fires "SELECT * FROM posts LIMIT 10"
+        #   }
+        #
+        # It is recommended to use the block form of unscoped because chaining
+        # unscoped with <tt>scope</tt> does not work.  Assuming that
+        # <tt>published</tt> is a <tt>scope</tt>, the following two statements
+        # are equal: the default_scope is applied on both.
+        #
+        #   Post.unscoped.published
+        #   Post.published
+        def unscoped #:nodoc:
+          block_given? ? relation.scoping { yield } : relation
+        end
+
+        def before_remove_const #:nodoc:
+          self.current_scope = nil
+        end
+
+        protected
+
+        # Use this macro in your model to set a default scope for all operations on
+        # the model.
+        #
+        #   class Article < ActiveRecord::Base
+        #     default_scope where(:published => true)
+        #   end
+        #
+        #   Article.all # => SELECT * FROM articles WHERE published = true
+        #
+        # The <tt>default_scope</tt> is also applied while creating/building a record. It is not
+        # applied while updating a record.
+        #
+        #   Article.new.published    # => true
+        #   Article.create.published # => true
+        #
+        # You can also use <tt>default_scope</tt> with a block, in order to have it lazily evaluated:
+        #
+        #   class Article < ActiveRecord::Base
+        #     default_scope { where(:published_at => Time.now - 1.week) }
+        #   end
+        #
+        # (You can also pass any object which responds to <tt>call</tt> to the <tt>default_scope</tt>
+        # macro, and it will be called when building the default scope.)
+        #
+        # If you use multiple <tt>default_scope</tt> declarations in your model then they will
+        # be merged together:
+        #
+        #   class Article < ActiveRecord::Base
+        #     default_scope where(:published => true)
+        #     default_scope where(:rating => 'G')
+        #   end
+        #
+        #   Article.all # => SELECT * FROM articles WHERE published = true AND rating = 'G'
+        #
+        # This is also the case with inheritance and module includes where the parent or module
+        # defines a <tt>default_scope</tt> and the child or including class defines a second one.
+        #
+        # If you need to do more complex things with a default scope, you can alternatively
+        # define it as a class method:
+        #
+        #   class Article < ActiveRecord::Base
+        #     def self.default_scope
+        #       # Should return a scope, you can call 'super' here etc.
+        #     end
+        #   end
+        def default_scope(scope = {})
+          scope = Proc.new if block_given?
+          self.default_scopes = default_scopes + [scope]
+        end
+
+        def build_default_scope #:nodoc:
+          if method(:default_scope).owner != ActiveRecord::Scoping::Default::ClassMethods
+            evaluate_default_scope { default_scope }
+          elsif default_scopes.any?
+            evaluate_default_scope do
+              default_scopes.inject(relation) do |default_scope, scope|
+                if scope.is_a?(Hash)
+                  default_scope.apply_finder_options(scope)
+                elsif !scope.is_a?(Relation) && scope.respond_to?(:call)
+                  default_scope.merge(scope.call)
+                else
+                  default_scope.merge(scope)
+                end
+              end
+            end
+          end
+        end
+
+        def ignore_default_scope? #:nodoc:
+          Thread.current["#{self}_ignore_default_scope"]
+        end
+
+        def ignore_default_scope=(ignore) #:nodoc:
+          Thread.current["#{self}_ignore_default_scope"] = ignore
+        end
+
+        # The ignore_default_scope flag is used to prevent an infinite recursion situation where
+        # a default scope references a scope which has a default scope which references a scope...
+        def evaluate_default_scope
+          return if ignore_default_scope?
+
+          begin
+            self.ignore_default_scope = true
+            yield
+          ensure
+            self.ignore_default_scope = false
+          end
+        end
+
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/scoping/named.rb b/activerecord/lib/active_record/scoping/named.rb
new file mode 100644
index 0000000000..0edc3f1dcc
--- /dev/null
+++ b/activerecord/lib/active_record/scoping/named.rb
@@ -0,0 +1,202 @@
+require 'active_support/core_ext/array'
+require 'active_support/core_ext/hash/except'
+require 'active_support/core_ext/kernel/singleton_class'
+require 'active_support/core_ext/object/blank'
+require 'active_support/core_ext/class/attribute'
+
+module ActiveRecord
+  # = Active Record Named \Scopes
+  module Scoping
+    module Named
+      extend ActiveSupport::Concern
+
+      module ClassMethods
+        # Returns an anonymous \scope.
+        #
+        #   posts = Post.scoped
+        #   posts.size # Fires "select count(*) from  posts" and returns the count
+        #   posts.each {|p| puts p.name } # Fires "select * from posts" and loads post objects
+        #
+        #   fruits = Fruit.scoped
+        #   fruits = fruits.where(:color => 'red') if options[:red_only]
+        #   fruits = fruits.limit(10) if limited?
+        #
+        # Anonymous \scopes tend to be useful when procedurally generating complex
+        # queries, where passing intermediate values (\scopes) around as first-class
+        # objects is convenient.
+        #
+        # You can define a \scope that applies to all finders using
+        # ActiveRecord::Base.default_scope.
+        def scoped(options = nil)
+          if options
+            scoped.apply_finder_options(options)
+          else
+            if current_scope
+              current_scope.clone
+            else
+              scope = relation.clone
+              scope.default_scoped = true
+              scope
+            end
+          end
+        end
+
+        ##
+        # Collects attributes from scopes that should be applied when creating
+        # an AR instance for the particular class this is called on.
+        def scope_attributes # :nodoc:
+          if current_scope
+            current_scope.scope_for_create
+          else
+            scope = relation.clone
+            scope.default_scoped = true
+            scope.scope_for_create
+          end
+        end
+
+        ##
+        # Are there default attributes associated with this scope?
+        def scope_attributes? # :nodoc:
+          current_scope || default_scopes.any?
+        end
+
+        # Adds a class method for retrieving and querying objects. A \scope represents a narrowing of a database query,
+        # such as <tt>where(:color => :red).select('shirts.*').includes(:washing_instructions)</tt>.
+        #
+        #   class Shirt < ActiveRecord::Base
+        #     scope :red, where(:color => 'red')
+        #     scope :dry_clean_only, joins(:washing_instructions).where('washing_instructions.dry_clean_only = ?', true)
+        #   end
+        #
+        # The above calls to <tt>scope</tt> define class methods Shirt.red and Shirt.dry_clean_only. Shirt.red,
+        # in effect, represents the query <tt>Shirt.where(:color => 'red')</tt>.
+        #
+        # Note that this is simply 'syntactic sugar' for defining an actual class method:
+        #
+        #   class Shirt < ActiveRecord::Base
+        #     def self.red
+        #       where(:color => 'red')
+        #     end
+        #   end
+        #
+        # Unlike <tt>Shirt.find(...)</tt>, however, the object returned by Shirt.red is not an Array; it
+        # resembles the association object constructed by a <tt>has_many</tt> declaration. For instance,
+        # you can invoke <tt>Shirt.red.first</tt>, <tt>Shirt.red.count</tt>, <tt>Shirt.red.where(:size => 'small')</tt>.
+        # Also, just as with the association objects, named \scopes act like an Array, implementing Enumerable;
+        # <tt>Shirt.red.each(&block)</tt>, <tt>Shirt.red.first</tt>, and <tt>Shirt.red.inject(memo, &block)</tt>
+        # all behave as if Shirt.red really was an Array.
+        #
+        # These named \scopes are composable. For instance, <tt>Shirt.red.dry_clean_only</tt> will produce
+        # all shirts that are both red and dry clean only.
+        # Nested finds and calculations also work with these compositions: <tt>Shirt.red.dry_clean_only.count</tt>
+        # returns the number of garments for which these criteria obtain. Similarly with
+        # <tt>Shirt.red.dry_clean_only.average(:thread_count)</tt>.
+        #
+        # All \scopes are available as class methods on the ActiveRecord::Base descendant upon which
+        # the \scopes were defined. But they are also available to <tt>has_many</tt> associations. If,
+        #
+        #   class Person < ActiveRecord::Base
+        #     has_many :shirts
+        #   end
+        #
+        # then <tt>elton.shirts.red.dry_clean_only</tt> will return all of Elton's red, dry clean
+        # only shirts.
+        #
+        # Named \scopes can also be procedural:
+        #
+        #   class Shirt < ActiveRecord::Base
+        #     scope :colored, lambda { |color| where(:color => color) }
+        #   end
+        #
+        # In this example, <tt>Shirt.colored('puce')</tt> finds all puce shirts.
+        #
+        # On Ruby 1.9 you can use the 'stabby lambda' syntax:
+        #
+        #   scope :colored, ->(color) { where(:color => color) }
+        #
+        # Note that scopes defined with \scope will be evaluated when they are defined, rather than
+        # when they are used. For example, the following would be incorrect:
+        #
+        #   class Post < ActiveRecord::Base
+        #     scope :recent, where('published_at >= ?', Time.current - 1.week)
+        #   end
+        #
+        # The example above would be 'frozen' to the <tt>Time.current</tt> value when the <tt>Post</tt>
+        # class was defined, and so the resultant SQL query would always be the same. The correct
+        # way to do this would be via a lambda, which will re-evaluate the scope each time
+        # it is called:
+        #
+        #   class Post < ActiveRecord::Base
+        #     scope :recent, lambda { where('published_at >= ?', Time.current - 1.week) }
+        #   end
+        #
+        # Named \scopes can also have extensions, just as with <tt>has_many</tt> declarations:
+        #
+        #   class Shirt < ActiveRecord::Base
+        #     scope :red, where(:color => 'red') do
+        #       def dom_id
+        #         'red_shirts'
+        #       end
+        #     end
+        #   end
+        #
+        # Scopes can also be used while creating/building a record.
+        #
+        #   class Article < ActiveRecord::Base
+        #     scope :published, where(:published => true)
+        #   end
+        #
+        #   Article.published.new.published    # => true
+        #   Article.published.create.published # => true
+        #
+        # Class methods on your model are automatically available
+        # on scopes. Assuming the following setup:
+        #
+        #   class Article < ActiveRecord::Base
+        #     scope :published, where(:published => true)
+        #     scope :featured, where(:featured => true)
+        #
+        #     def self.latest_article
+        #       order('published_at desc').first
+        #     end
+        #
+        #     def self.titles
+        #       map(&:title)
+        #     end
+        #
+        #   end
+        #
+        # We are able to call the methods like this:
+        #
+        #   Article.published.featured.latest_article
+        #   Article.featured.titles
+
+        def scope(name, scope_options = {})
+          name = name.to_sym
+          valid_scope_name?(name)
+          extension = Module.new(&Proc.new) if block_given?
+
+          scope_proc = lambda do |*args|
+            options = scope_options.respond_to?(:call) ? unscoped { scope_options.call(*args) } : scope_options
+            options = scoped.apply_finder_options(options) if options.is_a?(Hash)
+
+            relation = scoped.merge(options)
+
+            extension ? relation.extending(extension) : relation
+          end
+
+          singleton_class.send(:redefine_method, name, &scope_proc)
+        end
+
+      protected
+
+        def valid_scope_name?(name)
+          if respond_to?(name, true)
+            logger.warn "Creating scope :#{name}. " \
+                        "Overwriting existing method #{self.name}.#{name}."
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/session_store.rb b/activerecord/lib/active_record/session_store.rb
index 76c37cc367..e3bbd06f7e 100644
--- a/activerecord/lib/active_record/session_store.rb
+++ b/activerecord/lib/active_record/session_store.rb
@@ -59,12 +59,12 @@ module ActiveRecord
       end
 
       def drop_table!
-        connection_pool.clear_table_cache!(table_name)
+        connection.schema_cache.clear_table_cache!(table_name)
         connection.drop_table table_name
       end
 
       def create_table!
-        connection_pool.clear_table_cache!(table_name)
+        connection.schema_cache.clear_table_cache!(table_name)
         connection.create_table(table_name) do |t|
           t.string session_id_column, :limit => 255
           t.text data_column_name
diff --git a/activerecord/lib/active_record/store.rb b/activerecord/lib/active_record/store.rb
new file mode 100644
index 0000000000..8cc84f81d0
--- /dev/null
+++ b/activerecord/lib/active_record/store.rb
@@ -0,0 +1,50 @@
+module ActiveRecord
+  # Store gives you a thin wrapper around serialize for the purpose of storing hashes in a single column.
+  # It's like a simple key/value store backed into your record when you don't care about being able to
+  # query that store outside the context of a single record.
+  #
+  # You can then declare accessors to this store that are then accessible just like any other attribute
+  # of the model. This is very helpful for easily exposing store keys to a form or elsewhere that's
+  # already built around just accessing attributes on the model.
+  #
+  # Make sure that you declare the database column used for the serialized store as a text, so there's
+  # plenty of room.
+  #
+  # Examples:
+  #
+  #   class User < ActiveRecord::Base
+  #     store :settings, accessors: [ :color, :homepage ]
+  #   end
+  #   
+  #   u = User.new(color: 'black', homepage: '37signals.com')
+  #   u.color                          # Accessor stored attribute
+  #   u.settings[:country] = 'Denmark' # Any attribute, even if not specified with an accessor
+  #
+  #   # Add additional accessors to an existing store through store_accessor
+  #   class SuperUser < User
+  #     store_accessor :settings, :privileges, :servants
+  #   end
+  module Store
+    extend ActiveSupport::Concern
+  
+    module ClassMethods
+      def store(store_attribute, options = {})
+        serialize store_attribute, Hash
+        store_accessor(store_attribute, options[:accessors]) if options.has_key? :accessors
+      end
+
+      def store_accessor(store_attribute, *keys)
+        Array(keys).flatten.each do |key|
+          define_method("#{key}=") do |value|
+            send(store_attribute)[key] = value
+            send("#{store_attribute}_will_change!")
+          end
+    
+          define_method(key) do
+            send(store_attribute)[key]
+          end
+        end
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/activerecord/lib/active_record/test_case.rb b/activerecord/lib/active_record/test_case.rb
index ffe9b08dce..5398a14fc6 100644
--- a/activerecord/lib/active_record/test_case.rb
+++ b/activerecord/lib/active_record/test_case.rb
@@ -13,13 +13,6 @@ module ActiveRecord
       ActiveRecord::IdentityMap.clear
     end
 
-    # Backport skip to Ruby 1.8. test/unit doesn't support it, so just
-    # make it a noop.
-    unless instance_methods.map(&:to_s).include?("skip")
-      def skip(message)
-      end
-    end
-
     def assert_date_from_db(expected, actual, message = nil)
       # SybaseAdapter doesn't have a separate column type just for dates,
       # so the time is in the string and incorrectly formatted
@@ -56,18 +49,5 @@ module ActiveRecord
     ensure
       ActiveRecord::SQLCounter.ignored_sql = prev_ignored_sql
     end
-
-    def with_kcode(kcode)
-      if RUBY_VERSION < '1.9'
-        orig_kcode, $KCODE = $KCODE, kcode
-        begin
-          yield
-        ensure
-          $KCODE = orig_kcode
-        end
-      else
-        yield
-      end
-    end
   end
 end
diff --git a/activerecord/lib/active_record/timestamp.rb b/activerecord/lib/active_record/timestamp.rb
index 4d5e469a7f..c717fdea47 100644
--- a/activerecord/lib/active_record/timestamp.rb
+++ b/activerecord/lib/active_record/timestamp.rb
@@ -33,7 +33,7 @@ module ActiveRecord
     extend ActiveSupport::Concern
 
     included do
-      class_attribute :record_timestamps, :instance_writer => false
+      config_attribute :record_timestamps, :instance_writer => true
       self.record_timestamps = true
     end
 
diff --git a/activerecord/lib/active_record/transactions.rb b/activerecord/lib/active_record/transactions.rb
index d4870dd3f2..2c70d31b94 100644
--- a/activerecord/lib/active_record/transactions.rb
+++ b/activerecord/lib/active_record/transactions.rb
@@ -301,9 +301,9 @@ module ActiveRecord
     protected
 
     # Save the new record state and id of a record so it can be restored later if a transaction fails.
-    def remember_transaction_record_state #:nodoc
+    def remember_transaction_record_state #:nodoc:
       @_start_transaction_state ||= {}
-      @_start_transaction_state[:id] = id if self.class.primary_key?
+      @_start_transaction_state[:id] = id if has_attribute?(self.class.primary_key)
       unless @_start_transaction_state.include?(:new_record)
         @_start_transaction_state[:new_record] = @new_record
       end
@@ -314,7 +314,7 @@ module ActiveRecord
     end
 
     # Clear the new record state and id of a record.
-    def clear_transaction_record_state #:nodoc
+    def clear_transaction_record_state #:nodoc:
       if defined?(@_start_transaction_state)
         @_start_transaction_state[:level] = (@_start_transaction_state[:level] || 0) - 1
         remove_instance_variable(:@_start_transaction_state) if @_start_transaction_state[:level] < 1
@@ -322,7 +322,7 @@ module ActiveRecord
     end
 
     # Restore the new record state and id of a record that was previously saved by a call to save_record_state.
-    def restore_transaction_record_state(force = false) #:nodoc
+    def restore_transaction_record_state(force = false) #:nodoc:
       if defined?(@_start_transaction_state)
         @_start_transaction_state[:level] = (@_start_transaction_state[:level] || 0) - 1
         if @_start_transaction_state[:level] < 1
@@ -341,12 +341,12 @@ module ActiveRecord
     end
 
     # Determine if a record was created or destroyed in a transaction. State should be one of :new_record or :destroyed.
-    def transaction_record_state(state) #:nodoc
+    def transaction_record_state(state) #:nodoc:
       @_start_transaction_state[state] if defined?(@_start_transaction_state)
     end
 
     # Determine if a transaction included an action for :create, :update, or :destroy. Used in filtering callbacks.
-    def transaction_include_action?(action) #:nodoc
+    def transaction_include_action?(action) #:nodoc:
       case action
       when :create
         transaction_record_state(:new_record)
diff --git a/activerecord/lib/active_record/translation.rb b/activerecord/lib/active_record/translation.rb
new file mode 100644
index 0000000000..ddcb5f2a7a
--- /dev/null
+++ b/activerecord/lib/active_record/translation.rb
@@ -0,0 +1,22 @@
+module ActiveRecord
+  module Translation
+    include ActiveModel::Translation
+
+    # Set the lookup ancestors for ActiveModel.
+    def lookup_ancestors #:nodoc:
+      klass = self
+      classes = [klass]
+      return classes if klass == ActiveRecord::Base
+
+      while klass != klass.base_class
+        classes << klass = klass.superclass
+      end
+      classes
+    end
+
+    # Set the i18n scope to overwrite ActiveModel.
+    def i18n_scope #:nodoc:
+      :activerecord
+    end
+  end
+end
diff --git a/activerecord/lib/active_record/validations/associated.rb b/activerecord/lib/active_record/validations/associated.rb
index 7af0352a31..9f072c4c39 100644
--- a/activerecord/lib/active_record/validations/associated.rb
+++ b/activerecord/lib/active_record/validations/associated.rb
@@ -2,8 +2,9 @@ module ActiveRecord
   module Validations
     class AssociatedValidator < ActiveModel::EachValidator
       def validate_each(record, attribute, value)
-        return if (value.is_a?(Array) ? value : [value]).collect{ |r| r.nil? || r.valid? }.all?
-        record.errors.add(attribute, :invalid, options.merge(:value => value))
+        if Array.wrap(value).reject {|r| r.marked_for_destruction? || r.valid?}.any?
+          record.errors.add(attribute, :invalid, options.merge(:value => value))
+        end
       end
     end
 
diff --git a/activerecord/lib/active_record/validations/uniqueness.rb b/activerecord/lib/active_record/validations/uniqueness.rb
index 484b1d369b..2e2ea8c42b 100644
--- a/activerecord/lib/active_record/validations/uniqueness.rb
+++ b/activerecord/lib/active_record/validations/uniqueness.rb
@@ -57,8 +57,8 @@ module ActiveRecord
         value = column.limit ? value.to_s.mb_chars[0, column.limit] : value.to_s if column.text?
 
         if !options[:case_sensitive] && value && column.text?
-          # will use SQL LOWER function before comparison
-          relation = table[attribute].lower.eq(table.lower(value))
+          # will use SQL LOWER function before comparison, unless it detects a case insensitive collation
+          relation = klass.connection.case_insensitive_comparison(table, attribute, column, value)
         else
           value    = klass.connection.case_sensitive_modifier(value)
           relation = table[attribute].eq(value)
diff --git a/activerecord/lib/active_record/version.rb b/activerecord/lib/active_record/version.rb
index 838aa8fb1e..0c35adc11d 100644
--- a/activerecord/lib/active_record/version.rb
+++ b/activerecord/lib/active_record/version.rb
@@ -1,7 +1,7 @@
 module ActiveRecord
   module VERSION #:nodoc:
-    MAJOR = 3
-    MINOR = 2
+    MAJOR = 4
+    MINOR = 0
     TINY  = 0
     PRE   = "beta"