13 files changed, 382 insertions, 0 deletions
diff --git a/lib/active_relation/extensions.rb b/lib/active_relation/extensions.rb
new file mode 100644
index 0000000000..3751088483
--- /dev/null
+++ b/lib/active_relation/extensions.rb
@@ -0,0 +1,4 @@
+require 'active_relation/extensions/object'
+require 'active_relation/extensions/array'
+require 'active_relation/extensions/base'
+require 'active_relation/extensions/hash'
diff --git a/lib/active_relation/relations.rb b/lib/active_relation/relations.rb
new file mode 100644
index 0000000000..f7d1bc207a
--- /dev/null
+++ b/lib/active_relation/relations.rb
@@ -0,0 +1,12 @@
+require 'active_relation/relations/base'
+require 'active_relation/relations/compound'
+require 'active_relation/relations/table'
+require 'active_relation/relations/join'
+require 'active_relation/relations/attribute'
+require 'active_relation/relations/projection'
+require 'active_relation/relations/selection'
+require 'active_relation/relations/order'
+require 'active_relation/relations/range'
+require 'active_relation/relations/rename'
+require 'active_relation/relations/deletion'
+require 'active_relation/relations/insertion'
+\ No newline at end of file
diff --git a/lib/active_relation/relations/base.rb b/lib/active_relation/relations/base.rb
new file mode 100644
index 0000000000..c4a887eecd
--- /dev/null
+++ b/lib/active_relation/relations/base.rb
@@ -0,0 +1,111 @@
+module ActiveRelation
+  module Relations
+    class Base
+      include SqlBuilder
+  
+      module Iteration
+        include Enumerable
+    
+        def each(&block)
+          connection.select_all(to_s).each(&block)
+        end
+    
+        def first
+          connection.select_one(to_s)
+        end
+      end
+      include Iteration
+  
+      module Operations
+        def <=>(other)
+          JoinOperation.new("INNER JOIN", self, other)
+        end
+  
+        def <<(other)
+          JoinOperation.new("LEFT OUTER JOIN", self, other)
+        end
+  
+        def [](index)
+          case index
+          when Symbol
+            attribute(index)
+          when ::Range
+            Range.new(self, index)
+          end
+        end
+  
+        def include?(attribute)
+          Predicates::RelationInclusion.new(attribute, self)
+        end
+  
+        def select(*s)
+          Selection.new(self, *s)
+        end
+  
+        def project(*attributes)
+          Projection.new(self, *attributes)
+        end
+  
+        def order(*attributes)
+          Order.new(self, *attributes)
+        end
+    
+        def rename(attribute, aliaz)
+          Rename.new(self, attribute => aliaz)
+        end
+    
+        def insert(record)
+          Insertion.new(self, record)
+        end
+    
+        def delete
+          Deletion.new(self)
+        end
+    
+        class JoinOperation
+          attr_reader :join_sql, :relation1, :relation2
+
+          def initialize(join_sql, relation1, relation2)
+            @join_sql, @relation1, @relation2 = join_sql, relation1, relation2
+          end
+
+          def on(*predicates)
+            Join.new(join_sql, relation1, relation2, *predicates)
+          end
+
+          def ==(other)
+            (relation1 == other.relation1 and relation2 == other.relation2) or
+              (relation1 == other.relation2 and relation2 == other.relation1)
+          end
+        end
+      end
+      include Operations
+  
+      def connection
+        ActiveRecord::Base.connection
+      end
+  
+      def to_sql(options = {})
+        [
+          "SELECT #{attributes.collect{ |a| a.to_sql(:use_alias => true) }.join(', ')}",
+          "FROM #{quote_table_name(table)}",
+          (joins.to_sql(:quote => false) unless joins.blank?),
+          ("WHERE #{selects.collect{|s| s.to_sql(:quote => false)}.join("\n\tAND ")}" unless selects.blank?),
+          ("ORDER BY #{orders.collect(&:to_sql)}" unless orders.blank?),
+          ("LIMIT #{limit.to_sql}" unless limit.blank?),
+          ("OFFSET #{offset.to_sql}" unless offset.blank?)
+        ].compact.join("\n")
+      end
+      alias_method :to_s, :to_sql
+    
+      protected
+      def attributes; []  end
+      def selects;    []  end
+      def orders;     []  end
+      def inserts;    []  end
+      def joins;      nil end
+      def limit;      nil end
+      def offset;     nil end
+    end
+  end
+end
+\ No newline at end of file
diff --git a/lib/active_relation/relations/compound.rb b/lib/active_relation/relations/compound.rb
new file mode 100644
index 0000000000..442224a011
--- /dev/null
+++ b/lib/active_relation/relations/compound.rb
@@ -0,0 +1,9 @@
+module ActiveRelation
+  module Relations
+    class Compound < Base
+      attr_reader :relation
+  
+      delegate :attributes, :attribute, :joins, :selects, :orders, :table, :inserts, :limit, :offset, :to => :relation
+    end
+  end
+end
+\ No newline at end of file
diff --git a/lib/active_relation/relations/deletion.rb b/lib/active_relation/relations/deletion.rb
new file mode 100644
index 0000000000..f218d9da6d
--- /dev/null
+++ b/lib/active_relation/relations/deletion.rb
@@ -0,0 +1,17 @@
+module ActiveRelation
+  module Relations
+    class Deletion < Compound
+      def initialize(relation)
+        @relation = relation
+      end
+  
+      def to_sql(options = {})
+        [
+          "DELETE",
+          "FROM #{quote_table_name(table)}",
+          ("WHERE #{selects.collect(&:to_sql).join('\n\tAND ')}" unless selects.blank?)
+        ].compact.join("\n")
+      end  
+    end
+  end
+end
+\ No newline at end of file
diff --git a/lib/active_relation/relations/insertion.rb b/lib/active_relation/relations/insertion.rb
new file mode 100644
index 0000000000..a0042a18a5
--- /dev/null
+++ b/lib/active_relation/relations/insertion.rb
@@ -0,0 +1,25 @@
+module ActiveRelation
+  module Relations
+    class Insertion < Compound
+      attr_reader :record
+  
+      def initialize(relation, record)
+        @relation, @record = relation, record
+      end
+
+      def to_sql(options = {})
+        [
+          "INSERT",
+          "INTO #{quote_table_name(table)}",
+          "(#{record.keys.collect(&:to_sql).join(', ')})",
+          "VALUES #{inserts.collect(&:to_sql).join(', ')}"
+        ].join("\n")
+      end  
+
+      protected
+      def inserts
+        relation.inserts + [record]
+      end
+    end
+  end
+end
+\ No newline at end of file
diff --git a/lib/active_relation/relations/join.rb b/lib/active_relation/relations/join.rb
new file mode 100644
index 0000000000..1bd1439dd6
--- /dev/null
+++ b/lib/active_relation/relations/join.rb
@@ -0,0 +1,45 @@
+module ActiveRelation
+  module Relations
+    class Join < Base
+      attr_reader :join_sql, :relation1, :relation2, :predicates
+  
+      def initialize(join_sql, relation1, relation2, *predicates)
+        @join_sql, @relation1, @relation2, @predicates = join_sql, relation1, relation2, predicates
+      end
+  
+      def ==(other)
+        predicates == other.predicates and
+          ((relation1 == other.relation1 and relation2 == other.relation2) or
+          (relation2 == other.relation1 and relation1 == other.relation2))
+      end
+
+      def qualify
+        Join.new(join_sql, relation1.qualify, relation2.qualify, *predicates.collect(&:qualify))
+      end
+  
+      protected
+      def joins
+        [relation1.joins, relation2.joins, join].compact.join(" ")
+      end
+  
+      def selects
+        relation1.send(:selects) + relation2.send(:selects)
+      end
+  
+      def attributes
+        relation1.attributes + relation2.attributes
+      end
+  
+      def attribute(name)
+        relation1[name] || relation2[name]
+      end
+  
+      delegate :table, :to => :relation1
+  
+      private
+      def join
+        "#{join_sql} #{quote_table_name(relation2.table)} ON #{predicates.collect { |p| p.to_sql(:quote => false) }.join(' AND ')}"
+      end
+    end
+  end
+end
+\ No newline at end of file
diff --git a/lib/active_relation/relations/order.rb b/lib/active_relation/relations/order.rb
new file mode 100644
index 0000000000..99ff939528
--- /dev/null
+++ b/lib/active_relation/relations/order.rb
@@ -0,0 +1,19 @@
+module ActiveRelation
+  module Relations
+    class Order < Compound
+      attr_reader :relation, :orders
+  
+      def initialize(relation, *orders)
+        @relation, @orders = relation, orders
+      end
+  
+      def ==(other)
+        relation == other.relation and orders.eql?(other.orders)
+      end
+  
+      def qualify
+        Order.new(relation.qualify, *orders.collect { |o| o.qualify })
+      end
+    end
+  end
+end
+\ No newline at end of file
diff --git a/lib/active_relation/relations/projection.rb b/lib/active_relation/relations/projection.rb
new file mode 100644
index 0000000000..b30c76898d
--- /dev/null
+++ b/lib/active_relation/relations/projection.rb
@@ -0,0 +1,19 @@
+module ActiveRelation
+  module Relations
+    class Projection < Compound
+      attr_reader :relation, :attributes
+  
+      def initialize(relation, *attributes)
+        @relation, @attributes = relation, attributes
+      end
+  
+      def ==(other)
+        relation == other.relation and attributes.eql?(other.attributes)
+      end
+  
+      def qualify
+        Projection.new(relation.qualify, *attributes.collect(&:qualify))
+      end
+    end
+  end
+end
+\ No newline at end of file
diff --git a/lib/active_relation/relations/range.rb b/lib/active_relation/relations/range.rb
new file mode 100644
index 0000000000..d7e08efa06
--- /dev/null
+++ b/lib/active_relation/relations/range.rb
@@ -0,0 +1,23 @@
+module ActiveRelation
+  module Relations
+    class Range < Compound
+      attr_reader :range
+  
+      def initialize(relation, range)
+        @relation, @range = relation, range
+      end
+  
+      def ==(other)
+        relation == other.relation and range == other.range
+      end
+  
+      def limit
+        range.end - range.begin + 1
+      end
+  
+      def offset
+        range.begin
+      end
+    end
+  end
+end
+\ No newline at end of file
diff --git a/lib/active_relation/relations/rename.rb b/lib/active_relation/relations/rename.rb
new file mode 100644
index 0000000000..7a1693df57
--- /dev/null
+++ b/lib/active_relation/relations/rename.rb
@@ -0,0 +1,38 @@
+module ActiveRelation
+  module Relations
+    class Rename < Compound
+      attr_reader :relation, :schmattribute, :alias
+  
+      def initialize(relation, renames)
+        @schmattribute, @alias = renames.shift
+        @relation = renames.empty?? relation : Rename.new(relation, renames)
+      end
+  
+      def ==(other)
+        relation == other.relation and schmattribute.eql?(other.schmattribute) and self.alias == other.alias
+      end
+  
+      def attributes
+        relation.attributes.collect { |a| substitute(a) }
+      end
+  
+      def qualify
+        Rename.new(relation.qualify, schmattribute.qualify => self.alias)
+      end
+  
+      protected
+      def attribute(name)
+        case
+        when name == self.alias then schmattribute.alias(self.alias)
+        when relation[name].eql?(schmattribute) then nil
+        else relation[name]
+        end
+      end
+  
+      private
+      def substitute(a)
+        a.eql?(schmattribute) ? a.alias(self.alias) : a
+      end
+    end
+  end
+end
+\ No newline at end of file
diff --git a/lib/active_relation/relations/selection.rb b/lib/active_relation/relations/selection.rb
new file mode 100644
index 0000000000..e102d105a0
--- /dev/null
+++ b/lib/active_relation/relations/selection.rb
@@ -0,0 +1,25 @@
+module ActiveRelation
+  module Relations
+    class Selection < Compound
+      attr_reader :relation, :predicate
+  
+      def initialize(relation, *predicates)
+        @predicate = predicates.shift
+        @relation = predicates.empty?? relation : Selection.new(relation, *predicates)
+      end
+  
+      def ==(other)
+        relation == other.relation and predicate == other.predicate
+      end
+  
+      def qualify
+        Selection.new(relation.qualify, predicate.qualify)
+      end
+  
+      protected
+      def selects
+        relation.send(:selects) + [predicate]
+      end
+    end
+  end
+end
+\ No newline at end of file
diff --git a/lib/active_relation/relations/table.rb b/lib/active_relation/relations/table.rb
new file mode 100644
index 0000000000..38f540cc52
--- /dev/null
+++ b/lib/active_relation/relations/table.rb
@@ -0,0 +1,35 @@
+module ActiveRelation
+  module Relations
+    class Table < Base
+      attr_reader :table
+  
+      def initialize(table)
+        @table = table
+      end
+  
+      def attributes
+        attributes_by_name.values
+      end
+  
+      def qualify
+        Rename.new self, qualifications
+      end
+    
+      protected
+      def attribute(name)
+        attributes_by_name[name.to_s]
+      end
+  
+      private
+      def attributes_by_name
+        @attributes_by_name ||= connection.columns(table, "#{table} Columns").inject({}) do |attributes_by_name, column|
+          attributes_by_name.merge(column.name => ActiveRelation::Primitives::Attribute.new(self, column.name.to_sym))
+        end
+      end
+  
+      def qualifications
+        attributes.zip(attributes.collect(&:qualified_name)).to_hash
+      end
+    end
+  end
+end
+\ No newline at end of file