- The version_id_col feature on mapper() will raise a warning when

used with dialects that don't support "rowcount" adequately.
[ticket:1569]

2 files changed, 16 insertions, 5 deletions

diff --git a/lib/sqlalchemy/engine/default.py b/lib/sqlalchemy/engine/default.py
index fecc16b3c..40939d1a8 100644
--- a/lib/sqlalchemy/engine/default.py
+++ b/lib/sqlalchemy/engine/default.py
@@ -107,7 +107,11 @@ class DefaultDialect(base.Dialect):
         #self.supports_unicode_statements = True
         #self.supports_unicode_binds = True
         #self.returns_unicode_strings = True
-
+    
+    @property
+    def dialect_description(self):
+        return self.name + "+" + self.driver
+        
     def initialize(self, connection):
         try:
             self.server_version_info = self._get_server_version_info(connection)
diff --git a/lib/sqlalchemy/orm/mapper.py b/lib/sqlalchemy/orm/mapper.py
index 9b5583afa..881f0d546 100644
--- a/lib/sqlalchemy/orm/mapper.py
+++ b/lib/sqlalchemy/orm/mapper.py
@@ -1414,7 +1414,7 @@ class Mapper(object):
             if update:
                 mapper = table_to_mapper[table]
                 clause = sql.and_()
-
+                
                 for col in mapper._pks_by_table[table]:
                     clause.clauses.append(col == sql.bindparam(col._label, type_=col.type))
 
@@ -1429,9 +1429,16 @@ class Mapper(object):
 
                     rows += c.rowcount
 
-                if c.supports_sane_rowcount() and rows != len(update):
-                    raise exc.ConcurrentModificationError("Updated rowcount %d does not match number of objects updated %d" % (rows, len(update)))
-
+                if connection.dialect.supports_sane_rowcount:
+                    if rows != len(update):
+                        raise exc.ConcurrentModificationError(
+                                "Updated rowcount %d does not match number of objects updated %d" %
+                                (rows, len(update)))
+                        
+                elif mapper.version_id_col is not None:
+                    util.warn("Dialect %s does not support updated rowcount "
+                            "- versioning cannot be verified." % c.dialect.dialect_description)
+                    
             if insert:
                 statement = table.insert()
                 for state, params, mapper, connection, value_params in insert: