db.py 文件源码

def _param_marker(self):
        """Returns parameter marker based on paramstyle attribute if this database."""
        style = getattr(self, 'paramstyle', 'pyformat')

        if style == 'qmark':
            return '?'
        elif style == 'numeric':
            return ':1'
        elif style in ['format', 'pyformat']:
            return '%s'
        raise UnknownParamstyle(style)