__init__.py 文件源码

def _format_sql(self, sql, write_pk_field):
        last_pk = 0
        try:
            rows = self.write_db.query("SELECT MAX({}) max FROM {};".format(
                write_pk_field, self.write_table_name
            ))
        except (OperationalError, ProgrammingError):
            pass
        else:
            last_pk = next(rows)['max'] or last_pk
        return self.read_db.query(sql.format(last_pk))