1 files changed, 16 insertions, 46 deletions

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 7ff5001796..12b16b2473 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
@@ -83,6 +83,11 @@ module ActiveRecord
         exec_query(sql, name, binds)
       end
 
+      # Executes the truncate statement.
+      def truncate(table_name, name = nil)
+        raise NotImplementedError
+      end
+
       # Executes update +sql+ statement in the context of this connection using
       # +binds+ as the bind substitutes. +name+ is logged along with
       # the executed +sql+ statement.
@@ -193,7 +198,7 @@ module ActiveRecord
       # * You are creating a nested (savepoint) transaction
       #
       # The mysql, mysql2 and postgresql adapters support setting the transaction
-      # isolation level. However, support is disabled for mysql versions below 5,
+      # isolation level. However, support is disabled for MySQL versions below 5,
       # because they are affected by a bug[http://bugs.mysql.com/bug.php?id=39170]
       # which means the isolation level gets persisted outside the transaction.
       def transaction(options = {})
@@ -203,62 +208,30 @@ module ActiveRecord
           if options[:isolation]
             raise ActiveRecord::TransactionIsolationError, "cannot set isolation when joining a transaction"
           end
-
           yield
         else
-          within_new_transaction(options) { yield }
+          transaction_manager.within_new_transaction(options) { yield }
         end
       rescue ActiveRecord::Rollback
         # rollbacks are silently swallowed
       end
 
-      def within_new_transaction(options = {}) #:nodoc:
-        transaction = begin_transaction(options)
-        yield
-      rescue Exception => error
-        rollback_transaction if transaction
-        raise
-      ensure
-        begin
-          commit_transaction unless error
-        rescue Exception
-          rollback_transaction
-          raise
-        end
-      end
+      attr_reader :transaction_manager #:nodoc:
 
-      def open_transactions
-        @transaction.number
-      end
-
-      def current_transaction #:nodoc:
-        @transaction
-      end
+      delegate :within_new_transaction, :open_transactions, :current_transaction, :begin_transaction, :commit_transaction, :rollback_transaction, to: :transaction_manager
 
       def transaction_open?
-        @transaction.open?
-      end
-
-      def begin_transaction(options = {}) #:nodoc:
-        @transaction = @transaction.begin(options)
-      end
-
-      def commit_transaction #:nodoc:
-        @transaction = @transaction.commit
-      end
-
-      def rollback_transaction #:nodoc:
-        @transaction = @transaction.rollback
+        current_transaction.open?
       end
 
       def reset_transaction #:nodoc:
-        @transaction = ClosedTransaction.new(self)
+        @transaction_manager = TransactionManager.new(self)
       end
 
       # Register a record with the current transaction so that its after_commit and after_rollback callbacks
       # can be called.
       def add_transaction_record(record)
-        @transaction.add_record(record)
+        current_transaction.add_record(record)
       end
 
       # Begins the transaction (and turns off auto-committing).
@@ -314,10 +287,6 @@ module ActiveRecord
         "DEFAULT VALUES"
       end
 
-      def limited_update_conditions(where_sql, quoted_table_name, quoted_primary_key)
-        "WHERE #{quoted_primary_key} IN (SELECT #{quoted_primary_key} FROM #{quoted_table_name} #{where_sql})"
-      end
-
       # Sanitizes the given LIMIT parameter in order to prevent SQL injection.
       #
       # The +limit+ may be anything that can evaluate to a string via #to_s. It
@@ -338,8 +307,8 @@ module ActiveRecord
       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.
+      # 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:
         key = update.key
         subselect = subquery_for(key, select)
@@ -364,8 +333,9 @@ module ActiveRecord
 
         # Returns an ActiveRecord::Result instance.
         def select(sql, name = nil, binds = [])
+          exec_query(sql, name, binds)
         end
-        undef_method :select
+
 
         # Returns the last auto-generated ID from the affected table.
         def insert_sql(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil)