sql.py 文件源码

def _is_sqlalchemy_connectable(con):
    global _SQLALCHEMY_INSTALLED
    if _SQLALCHEMY_INSTALLED is None:
        try:
            import sqlalchemy
            _SQLALCHEMY_INSTALLED = True

            from distutils.version import LooseVersion
            ver = LooseVersion(sqlalchemy.__version__)
            # For sqlalchemy versions < 0.8.2, the BIGINT type is recognized
            # for a sqlite engine, which results in a warning when trying to
            # read/write a DataFrame with int64 values. (GH7433)
            if ver < '0.8.2':
                from sqlalchemy import BigInteger
                from sqlalchemy.ext.compiler import compiles

                @compiles(BigInteger, 'sqlite')
                def compile_big_int_sqlite(type_, compiler, **kw):
                    return 'INTEGER'
        except ImportError:
            _SQLALCHEMY_INSTALLED = False

    if _SQLALCHEMY_INSTALLED:
        import sqlalchemy
        return isinstance(con, sqlalchemy.engine.Connectable)
    else:
        return False