如何在Firebird SQL中测试对象存在？

SELECT COUNT(*) FROM rdb$relations WHERE rdb$relation_name = 'YOUR_TABLE_NAME';

EXECUTE BLOCK RETURNS (OBJECT_EXISTS INTEGER) AS
BEGIN
  OBJECT_EXISTS = 0;
  FOR SELECT 1 FROM rdb$relations WHERE rdb$relation_name = 'YOUR_TABLE_NAME' INTO OBJECT_EXISTS DO SUSPEND;
  SUSPEND;
END

EXECUTE STATEMENT 'SELECT 1 FROM rdb$relations WHERE rdb$relation_name = ?' ('YOUR_TABLE_NAME') INTO :OBJECT_EXISTS;