- [feature] Added "no_autoflush" context

manager to Session, used with with:
will temporarily disable autoflush.

3 files changed, 35 insertions, 1 deletions

diff --git a/lib/sqlalchemy/orm/session.py b/lib/sqlalchemy/orm/session.py
index ba6ceaeec..d01c1598a 100644
--- a/lib/sqlalchemy/orm/session.py
+++ b/lib/sqlalchemy/orm/session.py
@@ -978,6 +978,34 @@ class Session(object):
 
         return self._query_cls(entities, self, **kwargs)
 
+    @property
+    @util.contextmanager
+    def no_autoflush(self):
+        """Return a context manager that disables autoflush.
+        
+        e.g.::
+        
+            with session.no_autoflush:
+                
+                some_object = SomeClass()
+                session.add(some_object)
+                # won't autoflush
+                some_object.related_thing = session.query(SomeRelated).first()
+        
+        Operations that proceed within the ``with:`` block
+        will not be subject to flushes occurring upon query
+        access.  This is useful when initializing a series
+        of objects which involve existing database queries,
+        where the uncompleted object should not yet be flushed.
+        
+        New in 0.7.6.
+
+        """
+        autoflush = self.autoflush
+        self.autoflush = False
+        yield self
+        self.autoflush = autoflush
+
     def _autoflush(self):
         if self.autoflush and not self._flushing:
             self.flush()
diff --git a/lib/sqlalchemy/util/__init__.py b/lib/sqlalchemy/util/__init__.py
index 571294025..13914aa7d 100644
--- a/lib/sqlalchemy/util/__init__.py
+++ b/lib/sqlalchemy/util/__init__.py
@@ -7,7 +7,7 @@
 from compat import callable, cmp, reduce, defaultdict, py25_dict, \
     threading, py3k_warning, jython, pypy, win32, set_types, buffer, pickle, \
     update_wrapper, partial, md5_hex, decode_slice, dottedgetter,\
-    parse_qsl, any
+    parse_qsl, any, contextmanager
 
 from _collections import NamedTuple, ImmutableContainer, immutabledict, \
     Properties, OrderedProperties, ImmutableProperties, OrderedDict, \
diff --git a/lib/sqlalchemy/util/compat.py b/lib/sqlalchemy/util/compat.py
index 07652f3c6..99b92b1e3 100644
--- a/lib/sqlalchemy/util/compat.py
+++ b/lib/sqlalchemy/util/compat.py
@@ -57,6 +57,12 @@ buffer = buffer
 # end Py2K
 
 try:
+    from contextlib import contextmanager
+except ImportError:
+    def contextmanager(fn):
+        return fn
+
+try:
     from functools import update_wrapper
 except ImportError:
     def update_wrapper(wrapper, wrapped,