diff --git a/src/finder.h b/src/finder.h
index 70a6879..45fb539 100644
--- a/src/finder.h
+++ b/src/finder.h
@@ -1215,12 +1215,12 @@ protected:
 		was_query_error = false;
 		last_query_error.clear();
 		use_table_prefix_for_fetching = false;
+		set_db_expression();
 
 		if( model_connector )
 		{
 			if( out_stream )
 			{
-				set_db_expression();
 				out_stream->clear();
 			}
 			else
@@ -1372,6 +1372,12 @@ private:
 			if( db_connector )
 			{
 				db_expression = db_connector->get_expression();
+
+				if( db_expression )
+				{
+					db_expression->clear();
+					db_expression->allow_to_use_prefix(true);
+				}
 			}
 		}
 	}