operations.py 文件源码

def _index(self, name, tablename, columns, schema=None, **kw):
        t = sa_schema.Table(tablename or 'no_table', sa_schema.MetaData(),
            *[sa_schema.Column(n, NULLTYPE) for n in columns],
            schema=schema
        )
        return sa_schema.Index(name, *[t.c[n] for n in columns], **kw)