如何在Oracle數據庫中同時執行2個表中的刪除操作？

Question

在我的Oracle數據庫中，我希望從2個不同的表中刪除行。

問題是，如果我先從KENNEL中刪除行，那麼我想在DOG表中刪除的行不能被找到刪除。

以下是我的SQL statements從兩個表中刪除。

DELETE FROM KENNEL WHERE COUNTRY_ID IS NULL; 
DELETE FROM DOG WHERE ID IN (SELECT DOG_ID FROM KENNEL WHERE COUNTRY_ID IS NULL); 

我怎麼能解決這個問題，以使2只刪除發生在同時，並確保無論從表中的行被刪除？

注意：我無法從DOG中刪除KENNEL，因爲KENNEL是必須先刪除的子記錄。

Answer 1

我會做這個集刪除的，就像這樣：

-- delete rows from child table first 
DELETE FROM KENNEL WHERE COUNTRY_ID IS NULL; 

-- now delete any parent rows that don't have any child records 
DELETE FROM DOG WHERE ID not exists (SELECT DOG_ID FROM KENNEL); 

這樣做，這樣意味着，如果不是全部在狗窩表給定dog_id的country_ids都爲空的，你止跌」試圖刪除父記錄 - 如果您嘗試過，則會出錯。

Answer 2

UPDATE DOG SET [some non-key field] = 'XXX' WHERE ID IN (SELECT DOG_ID FROM KENNEL WHERE COUNTRY_ID IS NULL); 

DELETE FROM KENNEL WHERE COUNTRY_ID IS NULL; 

DELETE FROM DOG WHERE [non-key field] = 'XXX';