added basic support for making migrations

src/dbconnector.cpp

@@ -85,6 +85,28 @@ void DbConnector::set_log_queries(bool log_queries)
 }
 
 
+bool DbConnector::query(const PT::TextStream & stream)
+{
+	std::unique_ptr<QueryResult> query_result_ptr(create_query_result());
+	return query(stream, *query_result_ptr);
+}
+
+
+bool DbConnector::query(const std::string & query_str)
+{
+	std::unique_ptr<QueryResult> query_result_ptr(create_query_result());
+	return query(query_str, *query_result_ptr);
+}
+
+
+bool DbConnector::query(const char * query_str)
+{
+	std::unique_ptr<QueryResult> query_result_ptr(create_query_result());
+	return query(query_str, *query_result_ptr);
+}
+
+
+
 bool DbConnector::query(const PT::TextStream & stream, QueryResult & query_result)
 {
 	std::string query_str;