sqla_compat.py 文件源码

def _textual_index_column(table, text_):
    """a workaround for the Index construct's severe lack of flexibility"""
    if isinstance(text_, compat.string_types):
        c = Column(text_, sqltypes.NULLTYPE)
        table.append_column(c)
        return c
    elif isinstance(text_, TextClause):
        return _textual_index_element(table, text_)
    else:
        raise ValueError("String or text() construct expected")