- The system by which a :class:`.Column` considers itself to be an

"auto increment" column has been changed, such that autoincrement
is no longer implicitly enabled for a :class:`.Table` that has a
composite primary key.  In order to accommodate being able to enable
autoincrement for a composite PK member column while at the same time
maintaining SQLAlchemy's long standing behavior of enabling
implicit autoincrement for a single integer primary key, a third
state has been added to the :paramref:`.Column.autoincrement` parameter
``"auto"``, which is now the default. fixes #3216
- The MySQL dialect no longer generates an extra "KEY" directive when
generating CREATE TABLE DDL for a table using InnoDB with a
composite primary key with AUTO_INCREMENT on a column that isn't the
first column;  to overcome InnoDB's limitation here, the PRIMARY KEY
constraint is now generated with the AUTO_INCREMENT column placed
first in the list of columns.

1 files changed, 4 insertions, 1 deletions

diff --git a/lib/sqlalchemy/testing/schema.py b/lib/sqlalchemy/testing/schema.py
index 93b52ad58..257578668 100644
--- a/lib/sqlalchemy/testing/schema.py
+++ b/lib/sqlalchemy/testing/schema.py
@@ -71,9 +71,12 @@ def Column(*args, **kw):
         args = [arg for arg in args if not isinstance(arg, schema.ForeignKey)]
 
     col = schema.Column(*args, **kw)
-    if 'test_needs_autoincrement' in test_opts and \
+    if test_opts.get('test_needs_autoincrement', False) and \
             kw.get('primary_key', False):
 
+        if col.default is None and col.server_default is None:
+            col.autoincrement = True
+
         # allow any test suite to pick up on this
         col.info['test_needs_autoincrement'] = True