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

10 files changed, 879 insertions, 1133 deletions

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 ddfdb05297..61994d4a47 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
@@ -82,10 +82,11 @@ module ActiveRecord
         # default max pool size to 5
         @size = (spec.config[:pool] && spec.config[:pool].to_i) || 5
 
-        @connections = []
-        @checked_out = []
+        @connections         = []
+        @checked_out         = []
         @automatic_reconnect = true
-        @tables = {}
+        @tables              = {}
+        @visitor             = nil
 
         @columns     = Hash.new do |h, table_name|
           h[table_name] = with_connection do |conn|
@@ -298,8 +299,18 @@ module ActiveRecord
         :connected?, :disconnect!, :with => :@connection_mutex
 
       private
+
       def new_connection
-        ActiveRecord::Base.send(spec.adapter_method, spec.config)
+        connection = ActiveRecord::Base.send(spec.adapter_method, spec.config)
+
+        # 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
+
+        connection
       end
 
       def current_connection_id #:nodoc:
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 777ef15dfc..dc4a53034b 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
@@ -1,30 +1,39 @@
 module ActiveRecord
   module ConnectionAdapters # :nodoc:
     module DatabaseStatements
+      # Converts an arel AST to SQL
+      def to_sql(arel)
+        if arel.respond_to?(:ast)
+          visitor.accept(arel.ast)
+        else
+          arel
+        end
+      end
+
       # Returns an array of record hashes with the column names as keys and
       # column values as values.
-      def select_all(sql, name = nil, binds = [])
-        select(sql, name, binds)
+      def select_all(arel, name = nil, binds = [])
+        select(to_sql(arel), name, binds)
       end
 
       # Returns a record hash with the column names as keys and column values
       # as values.
-      def select_one(sql, name = nil)
-        result = select_all(sql, name)
+      def select_one(arel, name = nil)
+        result = select_all(arel, name)
         result.first if result
       end
 
       # Returns a single value from a record
-      def select_value(sql, name = nil)
-        if result = select_one(sql, name)
+      def select_value(arel, name = nil)
+        if result = select_one(arel, name)
           result.values.first
         end
       end
 
       # Returns an array of the values of the first column in a select:
       #   select_values("SELECT id FROM companies LIMIT 3") => [1,2,3]
-      def select_values(sql, name = nil)
-        result = select_rows(sql, name)
+      def select_values(arel, name = nil)
+        result = select_rows(to_sql(arel), name)
         result.map { |v| v[0] }
       end
 
@@ -74,20 +83,20 @@ module ActiveRecord
       #
       # If the next id was calculated in advance (as in Oracle), it should be
       # passed in as +id_value+.
-      def insert(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil, binds = [])
-        sql, binds = sql_for_insert(sql, pk, id_value, sequence_name, binds)
+      def insert(arel, name = nil, pk = nil, id_value = nil, sequence_name = nil, binds = [])
+        sql, binds = sql_for_insert(to_sql(arel), pk, id_value, sequence_name, binds)
         value      = exec_insert(sql, name, binds)
         id_value || last_inserted_id(value)
       end
 
       # Executes the update statement and returns the number of rows affected.
-      def update(sql, name = nil, binds = [])
-        exec_update(sql, name, binds)
+      def update(arel, name = nil, binds = [])
+        exec_update(to_sql(arel), name, binds)
       end
 
       # Executes the delete statement and returns the number of rows affected.
-      def delete(sql, name = nil, binds = [])
-        exec_delete(sql, name, binds)
+      def delete(arel, name = nil, binds = [])
+        exec_delete(to_sql(arel), name, binds)
       end
 
       # Checks whether there is currently no transaction active. This is done
@@ -297,6 +306,16 @@ module ActiveRecord
         end
       end
 
+      # The default strategy for an UPDATE with joins is to use a subquery. This doesn't work
+      # on mysql (even when aliasing the tables), but mysql allows using JOIN directly in
+      # an UPDATE statement, so in the mysql adapters we redefine this to do that.
+      def join_to_update(update, select) #:nodoc:
+        subselect = select.clone
+        subselect.projections = [update.key]
+
+        update.where update.key.in(subselect)
+      end
+
       protected
         # Returns an array of record hashes with the column names as keys and
         # column values as values.
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb b/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb
index 093c30aa42..27ff13ad89 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb
@@ -55,9 +55,10 @@ module ActiveRecord
         @query_cache.clear
       end
 
-      def select_all(sql, name = nil, binds = [])
+      def select_all(arel, name = nil, binds = [])
         if @query_cache_enabled
-          cache_sql(sql, binds) { super }
+          sql = to_sql(arel)
+          cache_sql(sql, binds) { super(sql, name, binds) }
         else
           super
         end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
index bde31d1cda..443e61b527 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
@@ -2,21 +2,33 @@ require 'date'
 require 'bigdecimal'
 require 'bigdecimal/util'
 require 'active_support/core_ext/benchmark'
-
-# TODO: Autoload these files
-require 'active_record/connection_adapters/column'
-require 'active_record/connection_adapters/abstract/schema_definitions'
-require 'active_record/connection_adapters/abstract/schema_statements'
-require 'active_record/connection_adapters/abstract/database_statements'
-require 'active_record/connection_adapters/abstract/quoting'
-require 'active_record/connection_adapters/abstract/connection_pool'
-require 'active_record/connection_adapters/abstract/connection_specification'
-require 'active_record/connection_adapters/abstract/query_cache'
-require 'active_record/connection_adapters/abstract/database_limits'
-require 'active_record/result'
+require 'active_support/deprecation'
 
 module ActiveRecord
   module ConnectionAdapters # :nodoc:
+    extend ActiveSupport::Autoload
+
+    autoload :Column
+
+    autoload_under 'abstract' do
+      autoload :IndexDefinition,  'active_record/connection_adapters/abstract/schema_definitions'
+      autoload :ColumnDefinition, 'active_record/connection_adapters/abstract/schema_definitions'
+      autoload :TableDefinition,  'active_record/connection_adapters/abstract/schema_definitions'
+      autoload :Table,            'active_record/connection_adapters/abstract/schema_definitions'
+
+      autoload :SchemaStatements
+      autoload :DatabaseStatements
+      autoload :DatabaseLimits
+      autoload :Quoting
+
+      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
+
     # Active Record supports multiple database systems. AbstractAdapter and
     # related classes form the abstraction layer which makes this possible.
     # An AbstractAdapter represents a connection to a database, and provides an
@@ -38,6 +50,8 @@ module ActiveRecord
 
       define_callbacks :checkout, :checkin
 
+      attr_accessor :visitor
+
       def initialize(connection, logger = nil) #:nodoc:
         @active = nil
         @connection, @logger = connection, logger
@@ -45,6 +59,25 @@ module ActiveRecord
         @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)
+        end
       end
 
       # Returns the human-readable name of the adapter. Use mixed case - one
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
new file mode 100644
index 0000000000..4b7c74e0b8
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -0,0 +1,611 @@
+require 'active_support/core_ext/object/blank'
+
+module ActiveRecord
+  module ConnectionAdapters
+    class AbstractMysqlAdapter < AbstractAdapter
+      class Column < ConnectionAdapters::Column # :nodoc:
+        def extract_default(default)
+          if sql_type =~ /blob/i || type == :text
+            if default.blank?
+              return null ? nil : ''
+            else
+              raise ArgumentError, "#{type} columns cannot have a default value: #{default.inspect}"
+            end
+          elsif missing_default_forged_as_empty_string?(default)
+            nil
+          else
+            super
+          end
+        end
+
+        def has_default?
+          return false if sql_type =~ /blob/i || type == :text #mysql forbids defaults on blob and text columns
+          super
+        end
+
+        # Must return the relevant concrete adapter
+        def adapter
+          raise NotImplementedError
+        end
+
+        private
+
+        def simplified_type(field_type)
+          return :boolean if adapter.emulate_booleans && field_type.downcase.index("tinyint(1)")
+
+          case field_type
+          when /enum/i, /set/i then :string
+          when /year/i         then :integer
+          when /bit/i          then :binary
+          else
+            super
+          end
+        end
+
+        def extract_limit(sql_type)
+          case sql_type
+          when /blob|text/i
+            case sql_type
+            when /tiny/i
+              255
+            when /medium/i
+              16777215
+            when /long/i
+              2147483647 # mysql only allows 2^31-1, not 2^32-1, somewhat inconsistently with the tiny/medium/normal cases
+            else
+              super # we could return 65535 here, but we leave it undecorated by default
+            end
+          when /^bigint/i;    8
+          when /^int/i;       4
+          when /^mediumint/i; 3
+          when /^smallint/i;  2
+          when /^tinyint/i;   1
+          else
+            super
+          end
+        end
+
+        # MySQL misreports NOT NULL column default when none is given.
+        # We can't detect this for columns which may have a legitimate ''
+        # default (string) but we can for others (integer, datetime, boolean,
+        # and the rest).
+        #
+        # Test whether the column has default '', is not null, and is not
+        # a type allowing default ''.
+        def missing_default_forged_as_empty_string?(default)
+          type != :string && !null && default == ''
+        end
+      end
+
+      ##
+      # :singleton-method:
+      # By default, the MysqlAdapter will consider all columns of type <tt>tinyint(1)</tt>
+      # as boolean. If you wish to disable this emulation (which was the default
+      # behavior in versions 0.13.1 and earlier) you can add the following line
+      # to your application.rb file:
+      #
+      #   ActiveRecord::ConnectionAdapters::Mysql[2]Adapter.emulate_booleans = false
+      class_attribute :emulate_booleans
+      self.emulate_booleans = true
+
+      LOST_CONNECTION_ERROR_MESSAGES = [
+        "Server shutdown in progress",
+        "Broken pipe",
+        "Lost connection to MySQL server during query",
+        "MySQL server has gone away" ]
+
+      QUOTED_TRUE, QUOTED_FALSE = '1', '0'
+
+      NATIVE_DATABASE_TYPES = {
+        :primary_key => "int(11) DEFAULT NULL auto_increment PRIMARY KEY",
+        :string      => { :name => "varchar", :limit => 255 },
+        :text        => { :name => "text" },
+        :integer     => { :name => "int", :limit => 4 },
+        :float       => { :name => "float" },
+        :decimal     => { :name => "decimal" },
+        :datetime    => { :name => "datetime" },
+        :timestamp   => { :name => "datetime" },
+        :time        => { :name => "time" },
+        :date        => { :name => "date" },
+        :binary      => { :name => "blob" },
+        :boolean     => { :name => "tinyint", :limit => 1 }
+      }
+
+      # FIXME: Make the first parameter more similar for the two adapters
+      def initialize(connection, logger, connection_options, config)
+        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)
+      end
+
+      def adapter_name #:nodoc:
+        self.class::ADAPTER_NAME
+      end
+
+      # Returns true, since this connection adapter supports migrations.
+      def supports_migrations?
+        true
+      end
+
+      def supports_primary_key?
+        true
+      end
+
+      # Returns true, since this connection adapter supports savepoints.
+      def supports_savepoints?
+        true
+      end
+
+      def supports_bulk_alter? #:nodoc:
+        true
+      end
+
+      def native_database_types
+        NATIVE_DATABASE_TYPES
+      end
+
+      # HELPER METHODS ===========================================
+
+      # The two drivers have slightly different ways of yielding hashes of results, so
+      # this method must be implemented to provide a uniform interface.
+      def each_hash(result) # :nodoc:
+        raise NotImplementedError
+      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)
+      end
+
+      # Must return the Mysql error number from the exception, if the exception has an
+      # error number.
+      def error_number(exception) # :nodoc:
+        raise NotImplementedError
+      end
+
+      # QUOTING ==================================================
+
+      def quote(value, column = nil)
+        if value.kind_of?(String) && column && column.type == :binary && column.class.respond_to?(:string_to_binary)
+          s = column.class.string_to_binary(value).unpack("H*")[0]
+          "x'#{s}'"
+        elsif value.kind_of?(BigDecimal)
+          value.to_s("F")
+        else
+          super
+        end
+      end
+
+      def quote_column_name(name) #:nodoc:
+        @quoted_column_names[name] ||= "`#{name.to_s.gsub('`', '``')}`"
+      end
+
+      def quote_table_name(name) #:nodoc:
+        @quoted_table_names[name] ||= quote_column_name(name).gsub('.', '`.`')
+      end
+
+      def quoted_true
+        QUOTED_TRUE
+      end
+
+      def quoted_false
+        QUOTED_FALSE
+      end
+
+      # REFERENTIAL INTEGRITY ====================================
+
+      def disable_referential_integrity(&block) #:nodoc:
+        old = select_value("SELECT @@FOREIGN_KEY_CHECKS")
+
+        begin
+          update("SET FOREIGN_KEY_CHECKS = 0")
+          yield
+        ensure
+          update("SET FOREIGN_KEY_CHECKS = #{old}")
+        end
+      end
+
+      # DATABASE STATEMENTS ======================================
+
+      # Executes the SQL statement in the context of this connection.
+      def execute(sql, name = nil)
+        if name == :skip_logging
+          @connection.query(sql)
+        else
+          log(sql, name) { @connection.query(sql) }
+        end
+      rescue ActiveRecord::StatementInvalid => exception
+        if exception.message.split(":").first =~ /Packets out of order/
+          raise ActiveRecord::StatementInvalid, "'Packets out of order' error was received from the database. Please update your mysql bindings (gem install mysql) and read http://dev.mysql.com/doc/mysql/en/password-hashing.html for more information. If you're on Windows, use the Instant Rails installer to get the updated mysql bindings."
+        else
+          raise
+        end
+      end
+
+      # MysqlAdapter has to free a result after using it, so we use this method to write
+      # stuff in a abstract way without concerning ourselves about whether it needs to be
+      # explicitly freed or not.
+      def execute_and_free(sql, name = nil) #:nodoc:
+        yield execute(sql, name)
+      end
+
+      def update_sql(sql, name = nil) #:nodoc:
+        super
+        @connection.affected_rows
+      end
+
+      def begin_db_transaction
+        execute "BEGIN"
+      rescue Exception
+        # Transactions aren't supported
+      end
+
+      def commit_db_transaction #:nodoc:
+        execute "COMMIT"
+      rescue Exception
+        # Transactions aren't supported
+      end
+
+      def rollback_db_transaction #:nodoc:
+        execute "ROLLBACK"
+      rescue Exception
+        # Transactions aren't supported
+      end
+
+      def create_savepoint
+        execute("SAVEPOINT #{current_savepoint_name}")
+      end
+
+      def rollback_to_savepoint
+        execute("ROLLBACK TO SAVEPOINT #{current_savepoint_name}")
+      end
+
+      def release_savepoint
+        execute("RELEASE SAVEPOINT #{current_savepoint_name}")
+      end
+
+      # In the simple case, MySQL allows us to place JOINs directly into the UPDATE
+      # query. However, this does not allow for LIMIT, OFFSET and ORDER. To support
+      # these, we must use a subquery. However, MySQL is too stupid to create a
+      # temporary table for this automatically, so we have to give it some prompting
+      # in the form of a subsubquery. Ugh!
+      def join_to_update(update, select) #:nodoc:
+        if select.limit || select.offset || select.orders.any?
+          subsubselect = select.clone
+          subsubselect.projections = [update.key]
+
+          subselect = Arel::SelectManager.new(select.engine)
+          subselect.project Arel.sql(update.key.name)
+          subselect.from subsubselect.as('__active_record_temp')
+
+          update.where update.key.in(subselect)
+        else
+          update.table select.source
+          update.wheres = select.constraints
+        end
+      end
+
+      # SCHEMA STATEMENTS ========================================
+
+      def structure_dump #:nodoc:
+        if supports_views?
+          sql = "SHOW FULL TABLES WHERE Table_type = 'BASE TABLE'"
+        else
+          sql = "SHOW TABLES"
+        end
+
+        select_all(sql).map do |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("")
+      end
+
+      # Drops the database specified on the +name+ attribute
+      # and creates it again using the provided +options+.
+      def recreate_database(name, options = {})
+        drop_database(name)
+        create_database(name, options)
+      end
+
+      # Create a new MySQL database with optional <tt>:charset</tt> and <tt>:collation</tt>.
+      # Charset defaults to utf8.
+      #
+      # Example:
+      #   create_database 'charset_test', :charset => 'latin1', :collation => 'latin1_bin'
+      #   create_database 'matt_development'
+      #   create_database 'matt_development', :charset => :big5
+      def create_database(name, options = {})
+        if options[:collation]
+          execute "CREATE DATABASE `#{name}` DEFAULT CHARACTER SET `#{options[:charset] || 'utf8'}` COLLATE `#{options[:collation]}`"
+        else
+          execute "CREATE DATABASE `#{name}` DEFAULT CHARACTER SET `#{options[:charset] || 'utf8'}`"
+        end
+      end
+
+      # Drops a MySQL database.
+      #
+      # Example:
+      #   drop_database('sebastian_development')
+      def drop_database(name) #:nodoc:
+        execute "DROP DATABASE IF EXISTS `#{name}`"
+      end
+
+      def current_database
+        select_value 'SELECT DATABASE() as db'
+      end
+
+      # Returns the database character set.
+      def charset
+        show_variable 'character_set_database'
+      end
+
+      # Returns the database collation strategy.
+      def collation
+        show_variable 'collation_database'
+      end
+
+      def tables(name = nil, database = nil) #:nodoc:
+        sql = ["SHOW TABLES", database].compact.join(' IN ')
+
+        execute_and_free(sql, 'SCHEMA') do |result|
+          result.collect { |field| field.first }
+        end
+      end
+
+      def table_exists?(name)
+        return true if super
+
+        name          = name.to_s
+        schema, table = name.split('.', 2)
+
+        unless table # A table was provided without a schema
+          table  = schema
+          schema = nil
+        end
+
+        tables(nil, schema).include? table
+      end
+
+      # Returns an array of indexes for the given table.
+      def indexes(table_name, name = nil) #:nodoc:
+        indexes = []
+        current_index = nil
+        execute_and_free("SHOW KEYS FROM #{quote_table_name(table_name)}", 'SCHEMA') do |result|
+          each_hash(result) do |row|
+            if current_index != row[:Key_name]
+              next if row[:Key_name] == 'PRIMARY' # skip the primary key
+              current_index = row[:Key_name]
+              indexes << IndexDefinition.new(row[:Table], row[:Key_name], row[:Non_unique].to_i == 0, [], [])
+            end
+
+            indexes.last.columns << row[:Column_name]
+            indexes.last.lengths << row[:Sub_part]
+          end
+        end
+
+        indexes
+      end
+
+      # 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)}"
+        execute_and_free(sql, 'SCHEMA') do |result|
+          each_hash(result).map do |field|
+            new_column(field[:Field], field[:Default], field[:Type], field[:Null] == "YES")
+          end
+        end
+      end
+
+      def create_table(table_name, options = {}) #:nodoc:
+        super(table_name, options.reverse_merge(:options => "ENGINE=InnoDB"))
+      end
+
+      def bulk_change_table(table_name, operations) #:nodoc:
+        sqls = operations.map do |command, args|
+          table, arguments = args.shift, args
+          method = :"#{command}_sql"
+
+          if respond_to?(method)
+            send(method, table, *arguments)
+          else
+            raise "Unknown method called : #{method}(#{arguments.inspect})"
+          end
+        end.flatten.join(", ")
+
+        execute("ALTER TABLE #{quote_table_name(table_name)} #{sqls}")
+      end
+
+      # Renames a table.
+      #
+      # Example:
+      #   rename_table('octopuses', 'octopi')
+      def rename_table(table_name, new_name)
+        execute "RENAME TABLE #{quote_table_name(table_name)} TO #{quote_table_name(new_name)}"
+      end
+
+      def add_column(table_name, column_name, type, options = {})
+        execute("ALTER TABLE #{quote_table_name(table_name)} #{add_column_sql(table_name, column_name, type, options)}")
+      end
+
+      def change_column_default(table_name, column_name, default)
+        column = column_for(table_name, column_name)
+        change_column table_name, column_name, column.sql_type, :default => default
+      end
+
+      def change_column_null(table_name, column_name, null, default = nil)
+        column = column_for(table_name, column_name)
+
+        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
+
+        change_column table_name, column_name, column.sql_type, :null => null
+      end
+
+      def change_column(table_name, column_name, type, options = {}) #:nodoc:
+        execute("ALTER TABLE #{quote_table_name(table_name)} #{change_column_sql(table_name, column_name, type, options)}")
+      end
+
+      def rename_column(table_name, column_name, new_column_name) #:nodoc:
+        execute("ALTER TABLE #{quote_table_name(table_name)} #{rename_column_sql(table_name, column_name, new_column_name)}")
+      end
+
+      # Maps logical Rails types to MySQL-specific data types.
+      def type_to_sql(type, limit = nil, precision = nil, scale = nil)
+        return super unless type.to_s == 'integer'
+
+        case limit
+        when 1; 'tinyint'
+        when 2; 'smallint'
+        when 3; 'mediumint'
+        when nil, 4, 11; 'int(11)'  # compatibility with MySQL default
+        when 5..8; 'bigint'
+        else raise(ActiveRecordError, "No integer type has byte size #{limit}")
+        end
+      end
+
+      def add_column_position!(sql, options)
+        if options[:first]
+          sql << " FIRST"
+        elsif options[:after]
+          sql << " AFTER #{quote_column_name(options[:after])}"
+        end
+      end
+
+      # SHOW VARIABLES LIKE 'name'
+      def show_variable(name)
+        variables = select_all("SHOW VARIABLES LIKE '#{name}'")
+        variables.first['Value'] unless variables.empty?
+      end
+
+      # 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
+        end
+      end
+
+      # Returns just a table's primary key
+      def primary_key(table)
+        pk_and_sequence = pk_and_sequence_for(table)
+        pk_and_sequence && pk_and_sequence.first
+      end
+
+      def case_sensitive_modifier(node)
+        Arel::Nodes::Bin.new(node)
+      end
+
+      def limited_update_conditions(where_sql, quoted_table_name, quoted_primary_key)
+        where_sql
+      end
+
+      protected
+
+      def quoted_columns_for_index(column_names, options = {})
+        length = options[:length] if options.is_a?(Hash)
+
+        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
+      end
+
+      def translate_exception(exception, message)
+        case error_number(exception)
+        when 1062
+          RecordNotUnique.new(message, exception)
+        when 1452
+          InvalidForeignKey.new(message, exception)
+        else
+          super
+        end
+      end
+
+      def add_column_sql(table_name, column_name, type, options = {})
+        add_column_sql = "ADD #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
+        add_column_options!(add_column_sql, options)
+        add_column_position!(add_column_sql, options)
+        add_column_sql
+      end
+
+      def change_column_sql(table_name, column_name, type, options = {})
+        column = column_for(table_name, column_name)
+
+        unless options_include_default?(options)
+          options[:default] = column.default
+        end
+
+        unless options.has_key?(:null)
+          options[:null] = column.null
+        end
+
+        change_column_sql = "CHANGE #{quote_column_name(column_name)} #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
+        add_column_options!(change_column_sql, options)
+        add_column_position!(change_column_sql, options)
+        change_column_sql
+      end
+
+      def rename_column_sql(table_name, column_name, new_column_name)
+        options = {}
+
+        if column = columns(table_name).find { |c| c.name == column_name.to_s }
+          options[:default] = column.default
+          options[:null] = column.null
+        else
+          raise ActiveRecordError, "No such column: #{table_name}.#{column_name}"
+        end
+
+        current_type = select_one("SHOW COLUMNS FROM #{quote_table_name(table_name)} LIKE '#{column_name}'")["Type"]
+        rename_column_sql = "CHANGE #{quote_column_name(column_name)} #{quote_column_name(new_column_name)} #{current_type}"
+        add_column_options!(rename_column_sql, options)
+        rename_column_sql
+      end
+
+      def remove_column_sql(table_name, *column_names)
+        columns_for_remove(table_name, *column_names).map {|column_name| "DROP #{column_name}" }
+      end
+      alias :remove_columns_sql :remove_column
+
+      def add_index_sql(table_name, column_name, options = {})
+        index_name, index_type, index_columns = add_index_options(table_name, column_name, options)
+        "ADD #{index_type} INDEX #{index_name} (#{index_columns})"
+      end
+
+      def remove_index_sql(table_name, options = {})
+        index_name = index_name_for_remove(table_name, options)
+        "DROP INDEX #{index_name}"
+      end
+
+      def add_timestamps_sql(table_name)
+        [add_column_sql(table_name, :created_at, :datetime), add_column_sql(table_name, :updated_at, :datetime)]
+      end
+
+      def remove_timestamps_sql(table_name)
+        [remove_column_sql(table_name, :updated_at), remove_column_sql(table_name, :created_at)]
+      end
+
+      private
+
+      def supports_views?
+        version[0] >= 5
+      end
+
+      def column_for(table_name, column_name)
+        unless column = columns(table_name).find { |c| c.name == column_name.to_s }
+          raise "No such column: #{table_name}.#{column_name}"
+        end
+        column
+      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 f9602bbe77..8b574518e5 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb
@@ -1,4 +1,4 @@
-# encoding: utf-8
+require 'active_record/connection_adapters/abstract_mysql_adapter'
 
 gem 'mysql2', '~> 0.3.6'
 require 'mysql2'
@@ -20,187 +20,51 @@ module ActiveRecord
   end
 
   module ConnectionAdapters
-    class Mysql2IndexDefinition < Struct.new(:table, :name, :unique, :columns, :lengths) #:nodoc:
-    end
+    class Mysql2Adapter < AbstractMysqlAdapter
 
-    class Mysql2Column < Column
-      BOOL = "tinyint(1)"
-      def extract_default(default)
-        if sql_type =~ /blob/i || type == :text
-          if default.blank?
-            return null ? nil : ''
-          else
-            raise ArgumentError, "#{type} columns cannot have a default value: #{default.inspect}"
-          end
-        elsif missing_default_forged_as_empty_string?(default)
-          nil
-        else
-          super
+      class Column < AbstractMysqlAdapter::Column # :nodoc:
+        def adapter
+          Mysql2Adapter
         end
       end
 
-      def has_default?
-        return false if sql_type =~ /blob/i || type == :text #mysql forbids defaults on blob and text columns
-        super
-      end
-
-      private
-        def simplified_type(field_type)
-          return :boolean if Mysql2Adapter.emulate_booleans && field_type.downcase.index(BOOL)
-
-          case field_type
-          when /enum/i, /set/i then :string
-          when /year/i         then :integer
-          when /bit/i          then :binary
-          else
-            super
-          end
-        end
-
-        def extract_limit(sql_type)
-          case sql_type
-          when /blob|text/i
-            case sql_type
-            when /tiny/i
-              255
-            when /medium/i
-              16777215
-            when /long/i
-              2147483647 # mysql only allows 2^31-1, not 2^32-1, somewhat inconsistently with the tiny/medium/normal cases
-            else
-              super # we could return 65535 here, but we leave it undecorated by default
-            end
-          when /^bigint/i;    8
-          when /^int/i;       4
-          when /^mediumint/i; 3
-          when /^smallint/i;  2
-          when /^tinyint/i;   1
-          else
-            super
-          end
-        end
-
-        # MySQL misreports NOT NULL column default when none is given.
-        # We can't detect this for columns which may have a legitimate ''
-        # default (string) but we can for others (integer, datetime, boolean,
-        # and the rest).
-        #
-        # Test whether the column has default '', is not null, and is not
-        # a type allowing default ''.
-        def missing_default_forged_as_empty_string?(default)
-          type != :string && !null && default == ''
-        end
-    end
-
-    class Mysql2Adapter < AbstractAdapter
-      cattr_accessor :emulate_booleans
-      self.emulate_booleans = true
-
       ADAPTER_NAME = 'Mysql2'
-      PRIMARY = "PRIMARY"
-
-      LOST_CONNECTION_ERROR_MESSAGES = [
-        "Server shutdown in progress",
-        "Broken pipe",
-        "Lost connection to MySQL server during query",
-        "MySQL server has gone away" ]
-
-      QUOTED_TRUE, QUOTED_FALSE = '1', '0'
-
-      NATIVE_DATABASE_TYPES = {
-        :primary_key => "int(11) DEFAULT NULL auto_increment PRIMARY KEY",
-        :string      => { :name => "varchar", :limit => 255 },
-        :text        => { :name => "text" },
-        :integer     => { :name => "int", :limit => 4 },
-        :float       => { :name => "float" },
-        :decimal     => { :name => "decimal" },
-        :datetime    => { :name => "datetime" },
-        :timestamp   => { :name => "datetime" },
-        :time        => { :name => "time" },
-        :date        => { :name => "date" },
-        :binary      => { :name => "blob" },
-        :boolean     => { :name => "tinyint", :limit => 1 }
-      }
 
       def initialize(connection, logger, connection_options, config)
-        super(connection, logger)
-        @connection_options, @config = connection_options, config
-        @quoted_column_names, @quoted_table_names = {}, {}
+        super
         configure_connection
       end
 
-      def adapter_name
-        ADAPTER_NAME
-      end
+      # HELPER METHODS ===========================================
 
-      # Returns true, since this connection adapter supports migrations.
-      def supports_migrations?
-        true
-      end
-
-      def supports_primary_key?
-        true
-      end
-
-      # Returns true, since this connection adapter supports savepoints.
-      def supports_savepoints?
-        true
-      end
-
-      def native_database_types
-        NATIVE_DATABASE_TYPES
-      end
-
-      # QUOTING ==================================================
-
-      def quote(value, column = nil)
-        if value.kind_of?(String) && column && column.type == :binary && column.class.respond_to?(:string_to_binary)
-          s = column.class.string_to_binary(value).unpack("H*")[0]
-          "x'#{s}'"
-        elsif value.kind_of?(BigDecimal)
-          value.to_s("F")
+      def each_hash(result) # :nodoc:
+        if block_given?
+          result.each(:as => :hash, :symbolize_keys => true) do |row|
+            yield row
+          end
         else
-          super
+          to_enum(:each_hash, result)
         end
       end
 
-      def quote_column_name(name) #:nodoc:
-        @quoted_column_names[name] ||= "`#{name}`"
+      def new_column(field, default, type, null) # :nodoc:
+        Column.new(field, default, type, null)
       end
 
-      def quote_table_name(name) #:nodoc:
-        @quoted_table_names[name] ||= quote_column_name(name).gsub('.', '`.`')
+      def error_number(exception)
+        exception.error_number if exception.respond_to?(:error_number)
       end
 
+      # QUOTING ==================================================
+
       def quote_string(string)
         @connection.escape(string)
       end
 
-      def quoted_true
-        QUOTED_TRUE
-      end
-
-      def quoted_false
-        QUOTED_FALSE
-      end
-
       def substitute_at(column, index)
         Arel.sql "\0"
       end
 
-      # REFERENTIAL INTEGRITY ====================================
-
-      def disable_referential_integrity(&block) #:nodoc:
-        old = select_value("SELECT @@FOREIGN_KEY_CHECKS")
-
-        begin
-          update("SET FOREIGN_KEY_CHECKS = 0")
-          yield
-        ensure
-          update("SET FOREIGN_KEY_CHECKS = #{old}")
-        end
-      end
-
       # CONNECTION MANAGEMENT ====================================
 
       def active?
@@ -213,11 +77,6 @@ module ActiveRecord
         connect
       end
 
-      # this is set to true in 2.3, but we don't want it to be
-      def requires_reloading?
-        false
-      end
-
       # Disconnects from the database if already connected.
       # Otherwise, this method does nothing.
       def disconnect!
@@ -273,17 +132,22 @@ module ActiveRecord
         # make sure we carry over any changes to ActiveRecord::Base.default_timezone that have been
         # made since we established the connection
         @connection.query_options[:database_timezone] = ActiveRecord::Base.default_timezone
-        if name == :skip_logging
-          @connection.query(sql)
-        else
-          log(sql, name) { @connection.query(sql) }
-        end
-      rescue ActiveRecord::StatementInvalid => exception
-        if exception.message.split(":").first =~ /Packets out of order/
-          raise ActiveRecord::StatementInvalid, "'Packets out of order' error was received from the database. Please update your mysql bindings (gem install mysql) and read http://dev.mysql.com/doc/mysql/en/password-hashing.html for more information. If you're on Windows, use the Instant Rails installer to get the updated mysql bindings."
-        else
-          raise
-        end
+
+        super
+      end
+
+      def exec_query(sql, name = 'SQL', binds = [])
+        result = execute(sql, name)
+        ActiveRecord::Result.new(result.fields, result.to_a)
+      end
+
+      alias exec_without_stmt exec_query
+
+      # Returns an array of record hashes with the column names as keys and
+      # column values as values.
+      def select(sql, name = nil, binds = [])
+        binds = binds.dup
+        exec_query(sql.gsub("\0") { quote(*binds.shift.reverse) }, name).to_a
       end
 
       def insert_sql(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil)
@@ -312,358 +176,35 @@ module ActiveRecord
         @connection.last_id
       end
 
-      def update_sql(sql, name = nil)
-        super
-        @connection.affected_rows
-      end
-
-      def begin_db_transaction
-        execute "BEGIN"
-      rescue Exception
-        # Transactions aren't supported
-      end
-
-      def commit_db_transaction
-        execute "COMMIT"
-      rescue Exception
-        # Transactions aren't supported
-      end
-
-      def rollback_db_transaction
-        execute "ROLLBACK"
-      rescue Exception
-        # Transactions aren't supported
-      end
-
-      def create_savepoint
-        execute("SAVEPOINT #{current_savepoint_name}")
-      end
-
-      def rollback_to_savepoint
-        execute("ROLLBACK TO SAVEPOINT #{current_savepoint_name}")
-      end
-
-      def release_savepoint
-        execute("RELEASE SAVEPOINT #{current_savepoint_name}")
-      end
-
-      # SCHEMA STATEMENTS ========================================
-
-      def structure_dump
-        if supports_views?
-          sql = "SHOW FULL TABLES WHERE Table_type = 'BASE TABLE'"
-        else
-          sql = "SHOW TABLES"
-        end
-
-        select_all(sql).inject("") do |structure, table|
-          table.delete('Table_type')
-          structure += select_one("SHOW CREATE TABLE #{quote_table_name(table.to_a.first.last)}")["Create Table"] + ";\n\n"
-        end
-      end
-
-      # Drops the database specified on the +name+ attribute
-      # and creates it again using the provided +options+.
-      def recreate_database(name, options = {})
-        drop_database(name)
-        create_database(name, options)
-      end
-
-      # Create a new MySQL database with optional <tt>:charset</tt> and <tt>:collation</tt>.
-      # Charset defaults to utf8.
-      #
-      # Example:
-      #   create_database 'charset_test', :charset => 'latin1', :collation => 'latin1_bin'
-      #   create_database 'matt_development'
-      #   create_database 'matt_development', :charset => :big5
-      def create_database(name, options = {})
-        if options[:collation]
-          execute "CREATE DATABASE `#{name}` DEFAULT CHARACTER SET `#{options[:charset] || 'utf8'}` COLLATE `#{options[:collation]}`"
-        else
-          execute "CREATE DATABASE `#{name}` DEFAULT CHARACTER SET `#{options[:charset] || 'utf8'}`"
-        end
-      end
-
-      # Drops a MySQL database.
-      #
-      # Example:
-      #   drop_database('sebastian_development')
-      def drop_database(name) #:nodoc:
-        execute "DROP DATABASE IF EXISTS `#{name}`"
-      end
-
-      def current_database
-        select_value 'SELECT DATABASE() as db'
-      end
-
-      # Returns the database character set.
-      def charset
-        show_variable 'character_set_database'
-      end
-
-      # Returns the database collation strategy.
-      def collation
-        show_variable 'collation_database'
-      end
-
-      def tables(name = nil, database = nil) #:nodoc:
-        sql = ["SHOW TABLES", database].compact.join(' IN ')
-        execute(sql, 'SCHEMA').collect do |field|
-          field.first
-        end
-      end
-
-      def table_exists?(name)
-        return true if super
-
-        name          = name.to_s
-        schema, table = name.split('.', 2)
-
-        unless table # A table was provided without a schema
-          table  = schema
-          schema = nil
-        end
-
-        tables(nil, schema).include? table
-      end
-
-      # Returns an array of indexes for the given table.
-      def indexes(table_name, name = nil)
-        indexes = []
-        current_index = nil
-        result = execute("SHOW KEYS FROM #{quote_table_name(table_name)}", 'SCHEMA')
-        result.each(:symbolize_keys => true, :as => :hash) do |row|
-          if current_index != row[:Key_name]
-            next if row[:Key_name] == PRIMARY # skip the primary key
-            current_index = row[:Key_name]
-            indexes << Mysql2IndexDefinition.new(row[:Table], row[:Key_name], row[:Non_unique] == 0, [], [])
-          end
-
-          indexes.last.columns << row[:Column_name]
-          indexes.last.lengths << row[:Sub_part]
-        end
-        indexes
-      end
-
-      # Returns an array of +Mysql2Column+ objects for the table specified by +table_name+.
-      def columns(table_name, name = nil)
-        sql = "SHOW FIELDS FROM #{quote_table_name(table_name)}"
-        columns = []
-        result = execute(sql, 'SCHEMA')
-        result.each(:symbolize_keys => true, :as => :hash) { |field|
-          columns << Mysql2Column.new(field[:Field], field[:Default], field[:Type], field[:Null] == "YES")
-        }
-        columns
-      end
-
-      def create_table(table_name, options = {})
-        super(table_name, options.reverse_merge(:options => "ENGINE=InnoDB"))
-      end
-
-      # Renames a table.
-      #
-      # Example:
-      #   rename_table('octopuses', 'octopi')
-      def rename_table(table_name, new_name)
-        execute "RENAME TABLE #{quote_table_name(table_name)} TO #{quote_table_name(new_name)}"
-      end
-
-      def add_column(table_name, column_name, type, options = {})
-        add_column_sql = "ALTER TABLE #{quote_table_name(table_name)} ADD #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
-        add_column_options!(add_column_sql, options)
-        add_column_position!(add_column_sql, options)
-        execute(add_column_sql)
-      end
-
-      def change_column_default(table_name, column_name, default)
-        column = column_for(table_name, column_name)
-        change_column table_name, column_name, column.sql_type, :default => default
-      end
-
-      def change_column_null(table_name, column_name, null, default = nil)
-        column = column_for(table_name, column_name)
-
-        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
-
-        change_column table_name, column_name, column.sql_type, :null => null
-      end
-
-      def change_column(table_name, column_name, type, options = {})
-        column = column_for(table_name, column_name)
-
-        unless options_include_default?(options)
-          options[:default] = column.default
-        end
-
-        unless options.has_key?(:null)
-          options[:null] = column.null
-        end
-
-        change_column_sql = "ALTER TABLE #{quote_table_name(table_name)} CHANGE #{quote_column_name(column_name)} #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
-        add_column_options!(change_column_sql, options)
-        add_column_position!(change_column_sql, options)
-        execute(change_column_sql)
-      end
+      private
 
-      def rename_column(table_name, column_name, new_column_name)
-        options = {}
-        if column = columns(table_name).find { |c| c.name == column_name.to_s }
-          options[:default] = column.default
-          options[:null] = column.null
-        else
-          raise ActiveRecordError, "No such column: #{table_name}.#{column_name}"
-        end
-        current_type = select_one("SHOW COLUMNS FROM #{quote_table_name(table_name)} LIKE '#{column_name}'")["Type"]
-        rename_column_sql = "ALTER TABLE #{quote_table_name(table_name)} CHANGE #{quote_column_name(column_name)} #{quote_column_name(new_column_name)} #{current_type}"
-        add_column_options!(rename_column_sql, options)
-        execute(rename_column_sql)
+      def connect
+        @connection = Mysql2::Client.new(@config)
+        configure_connection
       end
 
-      # Maps logical Rails types to MySQL-specific data types.
-      def type_to_sql(type, limit = nil, precision = nil, scale = nil)
-        return super unless type.to_s == 'integer'
-
-        case limit
-        when 1; 'tinyint'
-        when 2; 'smallint'
-        when 3; 'mediumint'
-        when nil, 4, 11; 'int(11)'  # compatibility with MySQL default
-        when 5..8; 'bigint'
-        else raise(ActiveRecordError, "No integer type has byte size #{limit}")
-        end
-      end
+      def configure_connection
+        @connection.query_options.merge!(:as => :array)
 
-      def add_column_position!(sql, options)
-        if options[:first]
-          sql << " FIRST"
-        elsif options[:after]
-          sql << " AFTER #{quote_column_name(options[:after])}"
-        end
-      end
+        # By default, MySQL 'where id is null' selects the last inserted id.
+        # Turn this off. http://dev.rubyonrails.org/ticket/6778
+        variable_assignments = ['SQL_AUTO_IS_NULL=0']
+        encoding = @config[:encoding]
 
-      # SHOW VARIABLES LIKE 'name'.
-      def show_variable(name)
-        variables = select_all("SHOW VARIABLES LIKE '#{name}'")
-        variables.first['Value'] unless variables.empty?
-      end
+        # make sure we set the encoding
+        variable_assignments << "NAMES '#{encoding}'" if encoding
 
-      # Returns a table's primary key and belonging sequence.
-      def pk_and_sequence_for(table)
-        keys = []
-        result = execute("DESCRIBE #{quote_table_name(table)}", 'SCHEMA')
-        result.each(:symbolize_keys => true, :as => :hash) do |row|
-          keys << row[:Field] if row[:Key] == "PRI"
-        end
-        keys.length == 1 ? [keys.first, nil] : nil
-      end
-
-      # Returns just a table's primary key
-      def primary_key(table)
-        pk_and_sequence = pk_and_sequence_for(table)
-        pk_and_sequence && pk_and_sequence.first
-      end
+        # increase timeout so mysql server doesn't disconnect us
+        wait_timeout = @config[:wait_timeout]
+        wait_timeout = 2592000 unless wait_timeout.is_a?(Fixnum)
+        variable_assignments << "@@wait_timeout = #{wait_timeout}"
 
-      def case_sensitive_modifier(node)
-        Arel::Nodes::Bin.new(node)
+        execute("SET #{variable_assignments.join(', ')}", :skip_logging)
       end
 
-      def limited_update_conditions(where_sql, quoted_table_name, quoted_primary_key)
-        where_sql
+      def version
+        @version ||= @connection.info[:version].scan(/^(\d+)\.(\d+)\.(\d+)/).flatten.map { |v| v.to_i }
       end
-
-      protected
-        def quoted_columns_for_index(column_names, options = {})
-          length = options[:length] if options.is_a?(Hash)
-
-          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
-        end
-
-        def translate_exception(exception, message)
-          return super unless exception.respond_to?(:error_number)
-
-          case exception.error_number
-          when 1062
-            RecordNotUnique.new(message, exception)
-          when 1452
-            InvalidForeignKey.new(message, exception)
-          else
-            super
-          end
-        end
-
-      private
-        def connect
-          @connection = Mysql2::Client.new(@config)
-          configure_connection
-        end
-
-        def configure_connection
-          @connection.query_options.merge!(:as => :array)
-
-          # By default, MySQL 'where id is null' selects the last inserted id.
-          # Turn this off. http://dev.rubyonrails.org/ticket/6778
-          variable_assignments = ['SQL_AUTO_IS_NULL=0']
-          encoding = @config[:encoding]
-
-          # make sure we set the encoding
-          variable_assignments << "NAMES '#{encoding}'" if encoding
-
-          # increase timeout so mysql server doesn't disconnect us
-          wait_timeout = @config[:wait_timeout]
-          wait_timeout = 2592000 unless wait_timeout.is_a?(Fixnum)
-          variable_assignments << "@@wait_timeout = #{wait_timeout}"
-
-          execute("SET #{variable_assignments.join(', ')}", :skip_logging)
-        end
-
-        # Returns an array of record hashes with the column names as keys and
-        # column values as values.
-        def select(sql, name = nil, binds = [])
-          binds = binds.dup
-          exec_query(sql.gsub("\0") { quote(*binds.shift.reverse) }, name).to_a
-        end
-
-        def exec_query(sql, name = 'SQL', binds = [])
-          @connection.query_options[:database_timezone] = ActiveRecord::Base.default_timezone
-
-          log(sql, name, binds) do
-            begin
-              result = @connection.query(sql)
-            rescue ActiveRecord::StatementInvalid => exception
-              if exception.message.split(":").first =~ /Packets out of order/
-                raise ActiveRecord::StatementInvalid, "'Packets out of order' error was received from the database. Please update your mysql bindings (gem install mysql) and read http://dev.mysql.com/doc/mysql/en/password-hashing.html for more information. If you're on Windows, use the Instant Rails installer to get the updated mysql bindings."
-              else
-                raise
-              end
-            end
-
-            ActiveRecord::Result.new(result.fields, result.to_a)
-          end
-        end
-
-        def supports_views?
-          version[0] >= 5
-        end
-
-        def version
-          @version ||= @connection.info[:version].scan(/^(\d+)\.(\d+)\.(\d+)/).flatten.map { |v| v.to_i }
-        end
-
-        def column_for(table_name, column_name)
-          unless column = columns(table_name).find { |c| c.name == column_name.to_s }
-            raise "No such column: #{table_name}.#{column_name}"
-          end
-          column
-        end
     end
   end
 end
diff --git a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
index 9e6cb13cca..e9bdcc2104 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
@@ -1,6 +1,5 @@
-require 'active_record/connection_adapters/abstract_adapter'
-require 'active_support/core_ext/object/blank'
-require 'set'
+require 'active_record/connection_adapters/abstract_mysql_adapter'
+require 'active_support/core_ext/hash/keys'
 
 gem 'mysql', '~> 2.8.1'
 require 'mysql'
@@ -40,9 +39,29 @@ module ActiveRecord
   end
 
   module ConnectionAdapters
-    class MysqlColumn < Column #:nodoc:
-      class << self
-        def string_to_time(value)
+    # The MySQL adapter will work with both Ruby/MySQL, which is a Ruby-based MySQL adapter that comes bundled with Active Record, and with
+    # the faster C-based MySQL/Ruby adapter (available both as a gem and from http://www.tmtm.org/en/mysql/ruby/).
+    #
+    # Options:
+    #
+    # * <tt>:host</tt> - Defaults to "localhost".
+    # * <tt>:port</tt> - Defaults to 3306.
+    # * <tt>:socket</tt> - Defaults to "/tmp/mysql.sock".
+    # * <tt>:username</tt> - Defaults to "root"
+    # * <tt>:password</tt> - Defaults to nothing.
+    # * <tt>:database</tt> - The name of the database. No default, must be provided.
+    # * <tt>:encoding</tt> - (Optional) Sets the client encoding by executing "SET NAMES <encoding>" after connection.
+    # * <tt>:reconnect</tt> - Defaults to false (See MySQL documentation: http://dev.mysql.com/doc/refman/5.0/en/auto-reconnect.html).
+    # * <tt>:sslca</tt> - Necessary to use MySQL with an SSL connection.
+    # * <tt>:sslkey</tt> - Necessary to use MySQL with an SSL connection.
+    # * <tt>:sslcert</tt> - Necessary to use MySQL with an SSL connection.
+    # * <tt>:sslcapath</tt> - Necessary to use MySQL with an SSL connection.
+    # * <tt>:sslcipher</tt> - Necessary to use MySQL with an SSL connection.
+    #
+    class MysqlAdapter < AbstractMysqlAdapter
+
+      class Column < AbstractMysqlAdapter::Column #:nodoc:
+        def self.string_to_time(value)
           return super unless Mysql::Time === value
           new_time(
             value.year,
@@ -54,230 +73,69 @@ module ActiveRecord
             value.second_part)
         end
 
-        def string_to_dummy_time(v)
+        def self.string_to_dummy_time(v)
           return super unless Mysql::Time === v
           new_time(2000, 01, 01, v.hour, v.minute, v.second, v.second_part)
         end
 
-        def string_to_date(v)
+        def self.string_to_date(v)
           return super unless Mysql::Time === v
           new_date(v.year, v.month, v.day)
         end
-      end
 
-      def extract_default(default)
-        if sql_type =~ /blob/i || type == :text
-          if default.blank?
-            return null ? nil : ''
-          else
-            raise ArgumentError, "#{type} columns cannot have a default value: #{default.inspect}"
-          end
-        elsif missing_default_forged_as_empty_string?(default)
-          nil
-        else
-          super
+        def adapter
+          MysqlAdapter
         end
       end
 
-      def has_default?
-        return false if sql_type =~ /blob/i || type == :text #mysql forbids defaults on blob and text columns
-        super
-      end
-
-      private
-        def simplified_type(field_type)
-          return :boolean if MysqlAdapter.emulate_booleans && field_type.downcase.index("tinyint(1)")
-          return :string  if field_type =~ /enum/i
-          super
-        end
-
-        def extract_limit(sql_type)
-          case sql_type
-          when /blob|text/i
-            case sql_type
-            when /tiny/i
-              255
-            when /medium/i
-              16777215
-            when /long/i
-              2147483647 # mysql only allows 2^31-1, not 2^32-1, somewhat inconsistently with the tiny/medium/normal cases
-            else
-              super # we could return 65535 here, but we leave it undecorated by default
-            end
-          when /^bigint/i;    8
-          when /^int/i;       4
-          when /^mediumint/i; 3
-          when /^smallint/i;  2
-          when /^tinyint/i;   1
-          else
-            super
-          end
-        end
-
-        # MySQL misreports NOT NULL column default when none is given.
-        # We can't detect this for columns which may have a legitimate ''
-        # default (string) but we can for others (integer, datetime, boolean,
-        # and the rest).
-        #
-        # Test whether the column has default '', is not null, and is not
-        # a type allowing default ''.
-        def missing_default_forged_as_empty_string?(default)
-          type != :string && !null && default == ''
-        end
-    end
-
-    # The MySQL adapter will work with both Ruby/MySQL, which is a Ruby-based MySQL adapter that comes bundled with Active Record, and with
-    # the faster C-based MySQL/Ruby adapter (available both as a gem and from http://www.tmtm.org/en/mysql/ruby/).
-    #
-    # Options:
-    #
-    # * <tt>:host</tt> - Defaults to "localhost".
-    # * <tt>:port</tt> - Defaults to 3306.
-    # * <tt>:socket</tt> - Defaults to "/tmp/mysql.sock".
-    # * <tt>:username</tt> - Defaults to "root"
-    # * <tt>:password</tt> - Defaults to nothing.
-    # * <tt>:database</tt> - The name of the database. No default, must be provided.
-    # * <tt>:encoding</tt> - (Optional) Sets the client encoding by executing "SET NAMES <encoding>" after connection.
-    # * <tt>:reconnect</tt> - Defaults to false (See MySQL documentation: http://dev.mysql.com/doc/refman/5.0/en/auto-reconnect.html).
-    # * <tt>:sslca</tt> - Necessary to use MySQL with an SSL connection.
-    # * <tt>:sslkey</tt> - Necessary to use MySQL with an SSL connection.
-    # * <tt>:sslcert</tt> - Necessary to use MySQL with an SSL connection.
-    # * <tt>:sslcapath</tt> - Necessary to use MySQL with an SSL connection.
-    # * <tt>:sslcipher</tt> - Necessary to use MySQL with an SSL connection.
-    #
-    class MysqlAdapter < AbstractAdapter
-
-      ##
-      # :singleton-method:
-      # By default, the MysqlAdapter will consider all columns of type <tt>tinyint(1)</tt>
-      # as boolean. If you wish to disable this emulation (which was the default
-      # behavior in versions 0.13.1 and earlier) you can add the following line
-      # to your application.rb file:
-      #
-      #   ActiveRecord::ConnectionAdapters::MysqlAdapter.emulate_booleans = false
-      cattr_accessor :emulate_booleans
-      self.emulate_booleans = true
-
       ADAPTER_NAME = 'MySQL'
 
-      LOST_CONNECTION_ERROR_MESSAGES = [
-        "Server shutdown in progress",
-        "Broken pipe",
-        "Lost connection to MySQL server during query",
-        "MySQL server has gone away" ]
-
-      QUOTED_TRUE, QUOTED_FALSE = '1', '0'
-
-      NATIVE_DATABASE_TYPES = {
-        :primary_key => "int(11) DEFAULT NULL auto_increment PRIMARY KEY",
-        :string      => { :name => "varchar", :limit => 255 },
-        :text        => { :name => "text" },
-        :integer     => { :name => "int", :limit => 4 },
-        :float       => { :name => "float" },
-        :decimal     => { :name => "decimal" },
-        :datetime    => { :name => "datetime" },
-        :timestamp   => { :name => "datetime" },
-        :time        => { :name => "time" },
-        :date        => { :name => "date" },
-        :binary      => { :name => "blob" },
-        :boolean     => { :name => "tinyint", :limit => 1 }
-      }
-
       def initialize(connection, logger, connection_options, config)
-        super(connection, logger)
-        @connection_options, @config = connection_options, config
-        @quoted_column_names, @quoted_table_names = {}, {}
+        super
         @statements = {}
         @client_encoding = nil
         connect
       end
 
-      def adapter_name #:nodoc:
-        ADAPTER_NAME
-      end
-
-      def supports_bulk_alter? #:nodoc:
-        true
-      end
-
       # Returns true, since this connection adapter supports prepared statement
       # caching.
       def supports_statement_cache?
         true
       end
 
-      # Returns true, since this connection adapter supports migrations.
-      def supports_migrations? #:nodoc:
-        true
-      end
+      # HELPER METHODS ===========================================
 
-      # Returns true.
-      def supports_primary_key? #:nodoc:
-        true
+      def each_hash(result) # :nodoc:
+        if block_given?
+          result.each_hash do |row|
+            row.symbolize_keys!
+            yield row
+          end
+        else
+          to_enum(:each_hash, result)
+        end
       end
 
-      # Returns true, since this connection adapter supports savepoints.
-      def supports_savepoints? #:nodoc:
-        true
+      def new_column(field, default, type, null) # :nodoc:
+        Column.new(field, default, type, null)
       end
 
-      def native_database_types #:nodoc:
-        NATIVE_DATABASE_TYPES
+      def error_number(exception) # :nodoc:
+        exception.errno if exception.respond_to?(:errno)
       end
 
-
       # QUOTING ==================================================
 
-      def quote(value, column = nil)
-        if value.kind_of?(String) && column && column.type == :binary && column.class.respond_to?(:string_to_binary)
-          s = column.class.string_to_binary(value).unpack("H*")[0]
-          "x'#{s}'"
-        elsif value.kind_of?(BigDecimal)
-          value.to_s("F")
-        else
-          super
-        end
-      end
-
       def type_cast(value, column)
         return super unless value == true || value == false
 
         value ? 1 : 0
       end
 
-      def quote_column_name(name) #:nodoc:
-        @quoted_column_names[name] ||= "`#{name}`"
-      end
-
-      def quote_table_name(name) #:nodoc:
-        @quoted_table_names[name] ||= quote_column_name(name).gsub('.', '`.`')
-      end
-
       def quote_string(string) #:nodoc:
         @connection.quote(string)
       end
 
-      def quoted_true
-        QUOTED_TRUE
-      end
-
-      def quoted_false
-        QUOTED_FALSE
-      end
-
-      # REFERENTIAL INTEGRITY ====================================
-
-      def disable_referential_integrity #:nodoc:
-        old = select_value("SELECT @@FOREIGN_KEY_CHECKS")
-
-        begin
-          update("SET FOREIGN_KEY_CHECKS = 0")
-          yield
-        ensure
-          update("SET FOREIGN_KEY_CHECKS = #{old}")
-        end
-      end
-
       # CONNECTION MANAGEMENT ====================================
 
       def active?
@@ -421,20 +279,11 @@ module ActiveRecord
         end
       end
 
-      # Executes an SQL query and returns a MySQL::Result object. Note that you have to free
-      # the Result object after you're done using it.
-      def execute(sql, name = nil) #:nodoc:
-        if name == :skip_logging
-          @connection.query(sql)
-        else
-          log(sql, name) { @connection.query(sql) }
-        end
-      rescue ActiveRecord::StatementInvalid => exception
-        if exception.message.split(":").first =~ /Packets out of order/
-          raise ActiveRecord::StatementInvalid, "'Packets out of order' error was received from the database. Please update your mysql bindings (gem install mysql) and read http://dev.mysql.com/doc/mysql/en/password-hashing.html for more information. If you're on Windows, use the Instant Rails installer to get the updated mysql bindings."
-        else
-          raise
-        end
+      def execute_and_free(sql, name = nil)
+        result = execute(sql, name)
+        ret = yield result
+        result.free
+        ret
       end
 
       def insert_sql(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil) #:nodoc:
@@ -443,11 +292,6 @@ module ActiveRecord
       end
       alias :create :insert_sql
 
-      def update_sql(sql, name = nil) #:nodoc:
-        super
-        @connection.affected_rows
-      end
-
       def exec_delete(sql, name, binds)
         log(sql, name, binds) do
           exec_stmt(sql, name, binds) do |cols, stmt|
@@ -463,337 +307,8 @@ module ActiveRecord
         # Transactions aren't supported
       end
 
-      def commit_db_transaction #:nodoc:
-        execute "COMMIT"
-      rescue Exception
-        # Transactions aren't supported
-      end
-
-      def rollback_db_transaction #:nodoc:
-        execute "ROLLBACK"
-      rescue Exception
-        # Transactions aren't supported
-      end
-
-      def create_savepoint
-        execute("SAVEPOINT #{current_savepoint_name}")
-      end
-
-      def rollback_to_savepoint
-        execute("ROLLBACK TO SAVEPOINT #{current_savepoint_name}")
-      end
-
-      def release_savepoint
-        execute("RELEASE SAVEPOINT #{current_savepoint_name}")
-      end
-
-      # SCHEMA STATEMENTS ========================================
-
-      def structure_dump #:nodoc:
-        if supports_views?
-          sql = "SHOW FULL TABLES WHERE Table_type = 'BASE TABLE'"
-        else
-          sql = "SHOW TABLES"
-        end
-
-        select_all(sql).map do |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("")
-      end
-
-      # Drops the database specified on the +name+ attribute
-      # and creates it again using the provided +options+.
-      def recreate_database(name, options = {}) #:nodoc:
-        drop_database(name)
-        create_database(name, options)
-      end
-
-      # Create a new MySQL database with optional <tt>:charset</tt> and <tt>:collation</tt>.
-      # Charset defaults to utf8.
-      #
-      # Example:
-      #   create_database 'charset_test', :charset => 'latin1', :collation => 'latin1_bin'
-      #   create_database 'matt_development'
-      #   create_database 'matt_development', :charset => :big5
-      def create_database(name, options = {})
-        if options[:collation]
-          execute "CREATE DATABASE `#{name}` DEFAULT CHARACTER SET `#{options[:charset] || 'utf8'}` COLLATE `#{options[:collation]}`"
-        else
-          execute "CREATE DATABASE `#{name}` DEFAULT CHARACTER SET `#{options[:charset] || 'utf8'}`"
-        end
-      end
-
-      # Drops a MySQL database.
-      #
-      # Example:
-      #   drop_database 'sebastian_development'
-      def drop_database(name) #:nodoc:
-        execute "DROP DATABASE IF EXISTS `#{name}`"
-      end
-
-      def current_database
-        select_value 'SELECT DATABASE() as db'
-      end
-
-      # Returns the database character set.
-      def charset
-        show_variable 'character_set_database'
-      end
-
-      # Returns the database collation strategy.
-      def collation
-        show_variable 'collation_database'
-      end
-
-      def tables(name = nil, database = nil) #:nodoc:
-        result = execute(["SHOW TABLES", database].compact.join(' IN '), 'SCHEMA')
-        tables = result.collect { |field| field[0] }
-        result.free
-        tables
-      end
-
-      def table_exists?(name)
-        return true if super
-
-        name          = name.to_s
-        schema, table = name.split('.', 2)
-
-        unless table # A table was provided without a schema
-          table  = schema
-          schema = nil
-        end
-
-        tables(nil, schema).include? table
-      end
-
-      # Returns an array of indexes for the given table.
-      def indexes(table_name, name = nil)#:nodoc:
-        indexes = []
-        current_index = nil
-        result = execute("SHOW KEYS FROM #{quote_table_name(table_name)}", name)
-        result.each do |row|
-          if current_index != row[2]
-            next if row[2] == "PRIMARY" # skip the primary key
-            current_index = row[2]
-            indexes << IndexDefinition.new(row[0], row[2], row[1] == "0", [], [])
-          end
-
-          indexes.last.columns << row[4]
-          indexes.last.lengths << row[7]
-        end
-        result.free
-        indexes
-      end
-
-      # Returns an array of +MysqlColumn+ objects for the table specified by +table_name+.
-      def columns(table_name, name = nil)#:nodoc:
-        sql = "SHOW FIELDS FROM #{quote_table_name(table_name)}"
-        result = execute(sql, 'SCHEMA')
-        columns = result.collect { |field| MysqlColumn.new(field[0], field[4], field[1], field[2] == "YES") }
-        result.free
-        columns
-      end
-
-      def create_table(table_name, options = {}) #:nodoc:
-        super(table_name, options.reverse_merge(:options => "ENGINE=InnoDB"))
-      end
-
-      # Renames a table.
-      #
-      # Example:
-      #   rename_table('octopuses', 'octopi')
-      def rename_table(table_name, new_name)
-        execute "RENAME TABLE #{quote_table_name(table_name)} TO #{quote_table_name(new_name)}"
-      end
-
-      def bulk_change_table(table_name, operations) #:nodoc:
-        sqls = operations.map do |command, args|
-          table, arguments = args.shift, args
-          method = :"#{command}_sql"
-
-          if respond_to?(method)
-            send(method, table, *arguments)
-          else
-            raise "Unknown method called : #{method}(#{arguments.inspect})"
-          end
-        end.flatten.join(", ")
-
-        execute("ALTER TABLE #{quote_table_name(table_name)} #{sqls}")
-      end
-
-      def add_column(table_name, column_name, type, options = {})
-        execute("ALTER TABLE #{quote_table_name(table_name)} #{add_column_sql(table_name, column_name, type, options)}")
-      end
-
-      def change_column_default(table_name, column_name, default) #:nodoc:
-        column = column_for(table_name, column_name)
-        change_column table_name, column_name, column.sql_type, :default => default
-      end
-
-      def change_column_null(table_name, column_name, null, default = nil)
-        column = column_for(table_name, column_name)
-
-        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
-
-        change_column table_name, column_name, column.sql_type, :null => null
-      end
-
-      def change_column(table_name, column_name, type, options = {}) #:nodoc:
-        execute("ALTER TABLE #{quote_table_name(table_name)} #{change_column_sql(table_name, column_name, type, options)}")
-      end
-
-      def rename_column(table_name, column_name, new_column_name) #:nodoc:
-        execute("ALTER TABLE #{quote_table_name(table_name)} #{rename_column_sql(table_name, column_name, new_column_name)}")
-      end
-
-      # Maps logical Rails types to MySQL-specific data types.
-      def type_to_sql(type, limit = nil, precision = nil, scale = nil)
-        return super unless type.to_s == 'integer'
-
-        case limit
-        when 1; 'tinyint'
-        when 2; 'smallint'
-        when 3; 'mediumint'
-        when nil, 4, 11; 'int(11)'  # compatibility with MySQL default
-        when 5..8; 'bigint'
-        else raise(ActiveRecordError, "No integer type has byte size #{limit}")
-        end
-      end
-
-      def add_column_position!(sql, options)
-        if options[:first]
-          sql << " FIRST"
-        elsif options[:after]
-          sql << " AFTER #{quote_column_name(options[:after])}"
-        end
-      end
-
-      # SHOW VARIABLES LIKE 'name'
-      def show_variable(name)
-        variables = select_all("SHOW VARIABLES LIKE '#{name}'")
-        variables.first['Value'] unless variables.empty?
-      end
-
-      # Returns a table's primary key and belonging sequence.
-      def pk_and_sequence_for(table) #:nodoc:
-        keys = []
-        result = execute("describe #{quote_table_name(table)}", 'SCHEMA')
-        result.each_hash do |h|
-          keys << h["Field"]if h["Key"] == "PRI"
-        end
-        result.free
-        keys.length == 1 ? [keys.first, nil] : nil
-      end
-
-      # Returns just a table's primary key
-      def primary_key(table)
-        pk_and_sequence = pk_and_sequence_for(table)
-        pk_and_sequence && pk_and_sequence.first
-      end
-
-      def case_sensitive_modifier(node)
-        Arel::Nodes::Bin.new(node)
-      end
-
-      def limited_update_conditions(where_sql, quoted_table_name, quoted_primary_key)
-        where_sql
-      end
-
-      protected
-        def quoted_columns_for_index(column_names, options = {})
-          length = options[:length] if options.is_a?(Hash)
-
-          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
-        end
-
-        def translate_exception(exception, message)
-          return super unless exception.respond_to?(:errno)
-
-          case exception.errno
-          when 1062
-            RecordNotUnique.new(message, exception)
-          when 1452
-            InvalidForeignKey.new(message, exception)
-          else
-            super
-          end
-        end
-
-        def add_column_sql(table_name, column_name, type, options = {})
-          add_column_sql = "ADD #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
-          add_column_options!(add_column_sql, options)
-          add_column_position!(add_column_sql, options)
-          add_column_sql
-        end
-
-        def remove_column_sql(table_name, *column_names)
-          columns_for_remove(table_name, *column_names).map {|column_name| "DROP #{column_name}" }
-        end
-        alias :remove_columns_sql :remove_column
-
-        def change_column_sql(table_name, column_name, type, options = {})
-          column = column_for(table_name, column_name)
-
-          unless options_include_default?(options)
-            options[:default] = column.default
-          end
-
-          unless options.has_key?(:null)
-            options[:null] = column.null
-          end
-
-          change_column_sql = "CHANGE #{quote_column_name(column_name)} #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
-          add_column_options!(change_column_sql, options)
-          add_column_position!(change_column_sql, options)
-          change_column_sql
-        end
-
-        def rename_column_sql(table_name, column_name, new_column_name)
-          options = {}
-
-          if column = columns(table_name).find { |c| c.name == column_name.to_s }
-            options[:default] = column.default
-            options[:null] = column.null
-          else
-            raise ActiveRecordError, "No such column: #{table_name}.#{column_name}"
-          end
-
-          current_type = select_one("SHOW COLUMNS FROM #{quote_table_name(table_name)} LIKE '#{column_name}'")["Type"]
-          rename_column_sql = "CHANGE #{quote_column_name(column_name)} #{quote_column_name(new_column_name)} #{current_type}"
-          add_column_options!(rename_column_sql, options)
-          rename_column_sql
-        end
-
-        def add_index_sql(table_name, column_name, options = {})
-          index_name, index_type, index_columns = add_index_options(table_name, column_name, options)
-          "ADD #{index_type} INDEX #{index_name} (#{index_columns})"
-        end
-
-        def remove_index_sql(table_name, options = {})
-          index_name = index_name_for_remove(table_name, options)
-          "DROP INDEX #{index_name}"
-        end
-
-        def add_timestamps_sql(table_name)
-          [add_column_sql(table_name, :created_at, :datetime), add_column_sql(table_name, :updated_at, :datetime)]
-        end
-
-        def remove_timestamps_sql(table_name)
-          [remove_column_sql(table_name, :updated_at), remove_column_sql(table_name, :created_at)]
-        end
-
       private
+
       def exec_stmt(sql, name, binds)
         cache = {}
         if binds.empty?
@@ -805,7 +320,6 @@ module ActiveRecord
           stmt = cache[:stmt]
         end
 
-
         begin
           stmt.execute(*binds.map { |col, val| type_cast(val, col) })
         rescue Mysql::Error => e
@@ -834,59 +348,48 @@ module ActiveRecord
         result
       end
 
-        def connect
-          encoding = @config[:encoding]
-          if encoding
-            @connection.options(Mysql::SET_CHARSET_NAME, encoding) rescue nil
-          end
-
-          if @config[:sslca] || @config[:sslkey]
-            @connection.ssl_set(@config[:sslkey], @config[:sslcert], @config[:sslca], @config[:sslcapath], @config[:sslcipher])
-          end
-
-          @connection.options(Mysql::OPT_CONNECT_TIMEOUT, @config[:connect_timeout]) if @config[:connect_timeout]
-          @connection.options(Mysql::OPT_READ_TIMEOUT, @config[:read_timeout]) if @config[:read_timeout]
-          @connection.options(Mysql::OPT_WRITE_TIMEOUT, @config[:write_timeout]) if @config[:write_timeout]
+      def connect
+        encoding = @config[:encoding]
+        if encoding
+          @connection.options(Mysql::SET_CHARSET_NAME, encoding) rescue nil
+        end
 
-          @connection.real_connect(*@connection_options)
+        if @config[:sslca] || @config[:sslkey]
+          @connection.ssl_set(@config[:sslkey], @config[:sslcert], @config[:sslca], @config[:sslcapath], @config[:sslcipher])
+        end
 
-          # reconnect must be set after real_connect is called, because real_connect sets it to false internally
-          @connection.reconnect = !!@config[:reconnect] if @connection.respond_to?(:reconnect=)
+        @connection.options(Mysql::OPT_CONNECT_TIMEOUT, @config[:connect_timeout]) if @config[:connect_timeout]
+        @connection.options(Mysql::OPT_READ_TIMEOUT, @config[:read_timeout]) if @config[:read_timeout]
+        @connection.options(Mysql::OPT_WRITE_TIMEOUT, @config[:write_timeout]) if @config[:write_timeout]
 
-          configure_connection
-        end
+        @connection.real_connect(*@connection_options)
 
-        def configure_connection
-          encoding = @config[:encoding]
-          execute("SET NAMES '#{encoding}'", :skip_logging) if encoding
+        # reconnect must be set after real_connect is called, because real_connect sets it to false internally
+        @connection.reconnect = !!@config[:reconnect] if @connection.respond_to?(:reconnect=)
 
-          # By default, MySQL 'where id is null' selects the last inserted id.
-          # Turn this off. http://dev.rubyonrails.org/ticket/6778
-          execute("SET SQL_AUTO_IS_NULL=0", :skip_logging)
-        end
+        configure_connection
+      end
 
-        def select(sql, name = nil, binds = [])
-          @connection.query_with_result = true
-          rows = exec_query(sql, name, binds).to_a
-          @connection.more_results && @connection.next_result    # invoking stored procedures with CLIENT_MULTI_RESULTS requires this to tidy up else connection will be dropped
-          rows
-        end
+      def configure_connection
+        encoding = @config[:encoding]
+        execute("SET NAMES '#{encoding}'", :skip_logging) if encoding
 
-        def supports_views?
-          version[0] >= 5
-        end
+        # By default, MySQL 'where id is null' selects the last inserted id.
+        # Turn this off. http://dev.rubyonrails.org/ticket/6778
+        execute("SET SQL_AUTO_IS_NULL=0", :skip_logging)
+      end
 
-        # Returns the version of the connected MySQL server.
-        def version
-          @version ||= @connection.server_info.scan(/^(\d+)\.(\d+)\.(\d+)/).flatten.map { |v| v.to_i }
-        end
+      def select(sql, name = nil, binds = [])
+        @connection.query_with_result = true
+        rows = exec_query(sql, name, binds).to_a
+        @connection.more_results && @connection.next_result    # invoking stored procedures with CLIENT_MULTI_RESULTS requires this to tidy up else connection will be dropped
+        rows
+      end
 
-        def column_for(table_name, column_name)
-          unless column = columns(table_name).find { |c| c.name == column_name.to_s }
-            raise "No such column: #{table_name}.#{column_name}"
-          end
-          column
-        end
+      # Returns the version of the connected MySQL server.
+      def version
+        @version ||= @connection.server_info.scan(/^(\d+)\.(\d+)\.(\d+)/).flatten.map { |v| v.to_i }
+      end
     end
   end
 end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index aefe69f8ed..ba4a6c7a78 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -265,6 +265,10 @@ 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.each_value do |value|
@@ -950,6 +954,8 @@ module ActiveRecord
       end
 
       module Utils
+        extend self
+
         # Returns an array of <tt>[schema_name, table_name]</tt> extracted from +name+.
         # +schema_name+ is nil if not specified in +name+.
         # +schema_name+ and +table_name+ exclude surrounding quotes (regardless of whether provided in +name+)
@@ -960,7 +966,7 @@ module ActiveRecord
         # * <tt>schema_name.table_name</tt>
         # * <tt>schema_name."table.name"</tt>
         # * <tt>"schema.name"."table name"</tt>
-        def self.extract_schema_and_table(name)
+        def extract_schema_and_table(name)
           table, schema = name.scan(/[^".\s]+|"[^"]*"/)[0..1].collect{|m| m.gsub(/(^"|"$)/,'') }.reverse
           [schema, table]
         end
diff --git a/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb b/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
index c3a7b039ff..0a0da0b5d3 100644
--- a/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
@@ -1,4 +1,6 @@
 require 'active_record/connection_adapters/sqlite_adapter'
+
+gem 'sqlite3', '~> 1.3.4'
 require 'sqlite3'
 
 module ActiveRecord
diff --git a/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb b/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb
index e2a0f63393..1996e49296 100644
--- a/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb
@@ -53,6 +53,10 @@ module ActiveRecord
         @config = config
       end
 
+      def self.visitor_for(pool) # :nodoc:
+        Arel::Visitors::SQLite.new(pool)
+      end
+
       def adapter_name #:nodoc:
         'SQLite'
       end
@@ -144,7 +148,7 @@ module ActiveRecord
       end
 
       def quote_column_name(name) #:nodoc:
-        %Q("#{name}")
+        %Q("#{name.to_s.gsub('"', '""')}")
       end
 
       # Quote date/time values for use in SQL input. Includes microseconds
@@ -157,10 +161,25 @@ module ActiveRecord
         end
       end
 
-      def type_cast(value, column) # :nodoc:
-        return super unless BigDecimal === value
+      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
 
-        value.to_f
+          value.to_f
+        end
       end
 
       # DATABASE STATEMENTS ======================================
@@ -238,15 +257,15 @@ module ActiveRecord
       end
 
       def begin_db_transaction #:nodoc:
-        @connection.transaction
+        log('begin transaction',nil) { @connection.transaction }
       end
 
       def commit_db_transaction #:nodoc:
-        @connection.commit
+        log('commit transaction',nil) { @connection.commit }
       end
 
       def rollback_db_transaction #:nodoc:
-        @connection.rollback
+        log('rollback transaction',nil) { @connection.rollback }
       end
 
       # SCHEMA STATEMENTS ========================================