Ticket #8316: db-mysqltypeissue.6.diff

django/db/backends/__init__.py

@@ -71 +71 @@
     interprets_empty_strings_as_nulls = False
     can_use_chunked_reads = True
     uses_savepoints = False
+    keys_need_similar_types = False
 
 class BaseDatabaseOperations(object):
     """

django/db/backends/mysql/base.py

@@ -68 +68 @@
 class DatabaseFeatures(BaseDatabaseFeatures):
     empty_fetchmany_value = ()
     update_can_self_select = False
+    keys_need_similar_types = True
 
 class DatabaseOperations(BaseDatabaseOperations):
     def date_extract_sql(self, lookup_type, field_name):

django/db/models/fields/related.py

@@ -712 +712 @@
         # of the field to which it points. An exception is if the ForeignKey
         # points to an AutoField/PositiveIntegerField/PositiveSmallIntegerField,
         # in which case the column type is simply that of an IntegerField.
+        # If the database needs similar types for key fields however, the only
+        # thing we can do is making AutoField an IntegerField.
         rel_field = self.rel.get_related_field()
-        if isinstance(rel_field, (AutoField, PositiveIntegerField, PositiveSmallIntegerField)):
-            return IntegerField().db_type()
+        if isinstance(rel_field, AutoField) \
+            or (not connection.features.keys_need_similar_types and 
+                isinstance(rel_field, (AutoField, 
+                                       PositiveIntegerField, 
+                                       PositiveSmallIntegerField))):
+            return IntegerField().db_type()
         return rel_field.db_type()
 
 class OneToOneField(ForeignKey):