防止刪除表中的所有行

Question

有沒有辦法阻止刪除表中的所有行？我知道如何使用DDL觸發器來防止刪除表格或截斷。我曾經無法突出顯示整個命令，將where子句關閉，並刪除表中的所有行。除非存在where子句，否則我希望防止這種情況再次發生。

Answer 1

你可以用觸發器來做到這一點。

CREATE TRIGGER dbo.KeepRows 
ON dbo.TableName 
FOR DELETE 
AS 
BEGIN 
    SET NOCOUNT ON; 

    IF NOT EXISTS (SELECT 1 FROM dbo.TableName) 
    BEGIN 
    RAISERROR('Naughty developer, you tried to delete the last row!', 11, 1); 
    ROLLBACK TRANSACTION; 
    END 
END 
GO 

爲了避免刪除，然後回滾，可以是如果表是大挺貴的，你可以改爲實現這個作爲替代觸發器，這將阻止任何工作情況的發生（除了檢查當然）。這是假設列id是主鍵：

CREATE TRIGGER dbo.KeepRows2 
ON dbo.TableName 
INSTEAD OF DELETE 
AS 
BEGIN 
    SET NOCOUNT ON; 

    IF EXISTS (SELECT 1 FROM dbo.TableName WHERE id NOT IN (SELECT id FROM deleted)) 
    BEGIN 
    DELETE dbo.TableName WHERE id IN (SELECT id FROM deleted); 
    END 
    -- optional: 
    ELSE 
    BEGIN 
    RAISERROR('Nice try, you need a WHERE clause!', 11, 1); 
    END 
END 
GO