防止删除表中的所有行

Question

有没有办法阻止删除表中的所有行？我知道如何使用DDL触发器来防止删除表格或截断。我曾经无法突出显示整个命令，将where子句关闭，并删除表中的所有行。除非存在where子句，否则我希望防止这种情况再次发生。

Answer 1

你可以用触发器来做到这一点。

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 

为了避免删除，然后回滚，可以是如果表是大挺贵的，你可以改为实现这个作为替代触发器，这将阻止任何工作情况的发生（除了检查当然）。这是假设列id是主键：

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