extras.py 文件源码

def _from_db(self, name, conn_or_curs):
        """Return a `CompositeCaster` instance for the type *name*.

        Raise `ProgrammingError` if the type is not found.
        """
        conn, curs = _solve_conn_curs(conn_or_curs)

        # Store the transaction status of the connection to revert it after use
        conn_status = conn.status

        # Use the correct schema
        if '.' in name:
            schema, tname = name.split('.', 1)
        else:
            tname = name
            schema = 'public'

        # column typarray not available before PG 8.3
        typarray = conn.server_version >= 80300 and "typarray" or "NULL"

        # get the type oid and attributes
        curs.execute("""\
SELECT t.oid, %s, attname, atttypid
FROM pg_type t
JOIN pg_namespace ns ON typnamespace = ns.oid
JOIN pg_attribute a ON attrelid = typrelid
WHERE typname = %%s AND nspname = %%s
    AND attnum > 0 AND NOT attisdropped
ORDER BY attnum;
""" % typarray, (tname, schema))

        recs = curs.fetchall()

        # revert the status of the connection as before the command
        if (conn_status != _ext.STATUS_IN_TRANSACTION
        and not conn.autocommit):
            conn.rollback()

        if not recs:
            raise psycopg2.ProgrammingError(
                "PostgreSQL type '%s' not found" % name)

        type_oid = recs[0][0]
        array_oid = recs[0][1]
        type_attrs = [ (r[2], r[3]) for r in recs ]

        return self(tname, type_oid, type_attrs,
            array_oid=array_oid, schema=schema)