Do not assume input SQL is ASCII

Fixes #16833

python/plugins/db_manager/db_plugins/connector.py

@@ -78,7 +78,7 @@ def _execute(self, cursor, sql):
         if cursor is None:
             cursor = self._get_cursor()
         try:
-            cursor.execute(str(sql))
+            cursor.execute(sql)
 
         except self.connection_error_types() as e:
             raise ConnectionError(e)

python/plugins/db_manager/db_plugins/data_model.py

@@ -144,7 +144,7 @@ def __init__(self, db, sql, parent=None):
 
         t = QTime()
         t.start()
-        c = self.db._execute(None, unicode(sql))
+        c = self.db._execute(None, sql)
         self._secs = t.elapsed() / 1000.0
         del t