- Fixed ORM bug where changing the primary key of an object, then marking

it for DELETE would fail to target the correct row for DELETE.
Then to compound matters, basic "number of rows matched" checks were
not being performed.  Both issues are fixed, however note that the
"rows matched" check requires so-called "sane multi-row count"
functionality; the DBAPI's executemany() method must count up the
rows matched by individual statements and SQLAlchemy's dialect must
mark this feature as supported, currently applies to some mysql dialects,
psycopg2, sqlite only. fixes #3006
- Enabled "sane multi-row count" checking for the psycopg2 DBAPI, as
this seems to be supported as of psycopg2 2.0.9.

1 files changed, 4 insertions, 1 deletions

diff --git a/lib/sqlalchemy/dialects/postgresql/psycopg2.py b/lib/sqlalchemy/dialects/postgresql/psycopg2.py
index 099ddf03d..ac1770625 100644
--- a/lib/sqlalchemy/dialects/postgresql/psycopg2.py
+++ b/lib/sqlalchemy/dialects/postgresql/psycopg2.py
@@ -347,7 +347,7 @@ class PGDialect_psycopg2(PGDialect):
         supports_unicode_statements = False
 
     default_paramstyle = 'pyformat'
-    supports_sane_multi_rowcount = False
+    supports_sane_multi_rowcount = False  # set to true based on psycopg2 version
     execution_ctx_cls = PGExecutionContext_psycopg2
     statement_compiler = PGCompiler_psycopg2
     preparer = PGIdentifierPreparer_psycopg2
@@ -393,6 +393,9 @@ class PGDialect_psycopg2(PGDialect):
                             is not None
         self._has_native_json = self.psycopg2_version >= (2, 5)
 
+        # http://initd.org/psycopg/docs/news.html#what-s-new-in-psycopg-2-0-9
+        self.supports_sane_multi_rowcount = self.psycopg2_version >= (2, 0, 9)
+
     @classmethod
     def dbapi(cls):
         import psycopg2