- Fixed issue when using :class:`.VARBINARY` type in conjunction with

an INSERT of NULL + pyodbc; pyodbc requires a special
object be passed in order to persist NULL.  As the :class:`.VARBINARY`
type is now usually the default for :class:`.LargeBinary` due to
:ticket:`3039`, this issue is partially a regression in 1.0.
The pymssql driver appears to be unaffected.
fixes #3464

1 files changed, 20 insertions, 2 deletions

diff --git a/lib/sqlalchemy/dialects/mssql/pyodbc.py b/lib/sqlalchemy/dialects/mssql/pyodbc.py
index ad1e7ae37..7ec8cbaa7 100644
--- a/lib/sqlalchemy/dialects/mssql/pyodbc.py
+++ b/lib/sqlalchemy/dialects/mssql/pyodbc.py
@@ -95,7 +95,7 @@ for unix + PyODBC.
 
 """
 
-from .base import MSExecutionContext, MSDialect
+from .base import MSExecutionContext, MSDialect, VARBINARY
 from ...connectors.pyodbc import PyODBCConnector
 from ... import types as sqltypes, util
 import decimal
@@ -174,6 +174,22 @@ class _MSFloat_pyodbc(_ms_numeric_pyodbc, sqltypes.Float):
     pass
 
 
+class _VARBINARY_pyodbc(VARBINARY):
+    def bind_processor(self, dialect):
+        if dialect.dbapi is None:
+            return None
+
+        DBAPIBinary = dialect.dbapi.Binary
+
+        def process(value):
+            if value is not None:
+                return DBAPIBinary(value)
+            else:
+                # pyodbc-specific
+                return dialect.dbapi.BinaryNull
+        return process
+
+
 class MSExecutionContext_pyodbc(MSExecutionContext):
     _embedded_scope_identity = False
 
@@ -230,7 +246,9 @@ class MSDialect_pyodbc(PyODBCConnector, MSDialect):
         MSDialect.colspecs,
         {
             sqltypes.Numeric: _MSNumeric_pyodbc,
-            sqltypes.Float: _MSFloat_pyodbc
+            sqltypes.Float: _MSFloat_pyodbc,
+            VARBINARY: _VARBINARY_pyodbc,
+            sqltypes.LargeBinary: _VARBINARY_pyodbc,
         }
     )