- merge r43460573c27a:4993c7eae8e5d117ff342bdc59f3b0635b898e2c of 0.6 branch

2 files changed, 22 insertions, 0 deletions

diff --git a/lib/sqlalchemy/engine/__init__.py b/lib/sqlalchemy/engine/__init__.py
index aebf35436..e33dff53b 100644
--- a/lib/sqlalchemy/engine/__init__.py
+++ b/lib/sqlalchemy/engine/__init__.py
@@ -175,6 +175,16 @@ def create_engine(*args, **kwargs):
         be applied to all connections.  See
         :meth:`~sqlalchemy.engine.base.Connection.execution_options`
 
+    :param implicit_returning=True: When ``False``, the RETURNING
+        feature of the database, if available, will not be used 
+        to fetch newly generated primary key values.   This applies
+        to those backends which support RETURNING or a compatible
+        construct, including Postgresql, Firebird, Oracle, Microsoft
+        SQL Server.  The default behavior is to use a compatible RETURNING
+        construct when a single-row INSERT statement is emitted with no 
+        existing returning() clause in order to fetch newly generated 
+        primary key values.
+
     :param label_length=None: optional integer value which limits
         the size of dynamically generated column labels to that many
         characters. If less than 6, labels are generated as
diff --git a/lib/sqlalchemy/engine/threadlocal.py b/lib/sqlalchemy/engine/threadlocal.py
index 2ce0922bf..d4d0488a9 100644
--- a/lib/sqlalchemy/engine/threadlocal.py
+++ b/lib/sqlalchemy/engine/threadlocal.py
@@ -71,16 +71,28 @@ class TLEngine(base.Engine):
         if not hasattr(self._connections, 'trans'):
             self._connections.trans = []
         self._connections.trans.append(self.contextual_connect().begin_twophase(xid=xid))
+        return self
 
     def begin_nested(self):
         if not hasattr(self._connections, 'trans'):
             self._connections.trans = []
         self._connections.trans.append(self.contextual_connect().begin_nested())
+        return self
 
     def begin(self):
         if not hasattr(self._connections, 'trans'):
             self._connections.trans = []
         self._connections.trans.append(self.contextual_connect().begin())
+        return self
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, type, value, traceback):
+        if type is None:
+            self.commit()
+        else:
+            self.rollback()
 
     def prepare(self):
         if not hasattr(self._connections, 'trans') or \