如何在SQL Server中創建before delete觸發器？

Question

我想創建一個before刪除觸發器。當我從表中刪除記錄時，必須將記錄插入到歷史記錄表中。我如何在SQL Server中執行此操作？

Answer 1

在這種情況下，你可能觸發「後」更好做有規律的。這是這種情況最常見的方法。

喜歡的東西

CREATE TRIGGER TRG_AUD_DEL 
ON yourTable 
FOR DELETE 
AS 
    INSERT INTO my_audit_table (col1, col2, ...) 
    SELECT col1, col2... 
    FROM DELETED 

會發生什麼事是，當一個記錄（或記錄！）從您的表中刪除，刪除的行會被插入到my_audit_table的DELETED表是包含一個虛擬表在刪除前立即記錄。

另外請注意，觸發運行作爲delete語句隱含的交易的一部分，因此，如果您刪除失敗並回滾，觸發也將回滾。

Answer 2

你也可以使用INSTEAD OF DELETE

CREATE TRIGGER dbo.SomeTableYouWhatToDeleteFrom 
ON dbo.YourTable 
INSTEAD OF DELETE 
AS 
BEGIN 

    -- Some code you want to do before delete 

    DELETE YourTable 
    FROM DELETED D 
    INNER JOIN dbo.YourTable T ON T.PK_1 = D.PK_1 
END 

Answer 3

這是可以做到在下面的步驟進行，讓我們在這個例子說，我使用的客戶表：

CREATE TABLE CUSTOMERS(
    ID INT    NOT NULL, 
    NAME VARCHAR (20)  NOT NULL, 
    AGE INT    NOT NULL, 
    ADDRESS CHAR (25) , 
    LAST_UPDATED DATETIME, 
    PRIMARY KEY (ID) 
); 

1. 創造歷史：

   CREATE TABLE CUSTOMERS_HIST( 
   ID INT    NOT NULL, 
   NAME VARCHAR (20)  NOT NULL, 
   AGE INT    NOT NULL, 
   ADDRESS CHAR (25) , 
   LAST_UPDATED DATETIME, 
   PRIMARY KEY (ID) 
   ); 
   

2. 觸發源表像下面的刪除事件：

   CREATE TRIGGER TRG_CUSTOMERS_DEL 
   ON CUSTOMERS 
   FOR DELETE 
   AS 
       INSERT INTO CUSTOMERS_HIST (ID, NAME, AGE, ADDRESS, LAST_UPDATED) 
       SELECT ID, NAME, AGE, ADDRESS, LAST_UPDATED 
       FROM DELETED