而不是插入触发器 SQL

Question

>我正在尝试创建一个"而不是插入触发器"，它不会让名称"john"将任何内容插入表中。 我的问题是，即使我将名称更改为其他名称，查询也会成功，但不会添加值。

任何帮助将不胜感激，提前感谢。

CREATE TRIGGER InsteadOfTrigger
ON Question4
INSTEAD OF INSERT
AS  
Declare @name varchar(50)
Declare @question varchar(50)
Declare @Answer char
Set @name = 'John'
IF (select Username from inserted) = @name
BEGIN
RAISERROR ('You have not paid up your fee', 10,1)
ROLLBACK TRANSACTION
END
ELSE
BEGIN
INSERT INTO question4
values (@name, @question, @Answer)
END

Answer 1

好的，

所以我删除了您的IF ELSE语句之间的BEGIN和END语句，并将触发器逻辑包装在BEGIN END

如下面的评论中所述，您不需要ROLLBACK TRANSACTION

此外，您还需要填充@question和@Answer，以便这些有用。

CREATE TRIGGER InsteadOfTrigger
ON Question4
INSTEAD OF INSERT
AS 
BEGIN
Declare @name varchar(50)
Declare @question varchar(50)
Declare @Answer char
Set @name = 'John'
IF (select Username from inserted) = @name
    RAISERROR ('You have not paid up your fee', 10,1)
    --ROLLBACK TRANSACTION
ELSE
    INSERT INTO question4
    values (@name, @question, @Answer)
END

Answer 2

嗯，我注意到您已经声明了，但实际上并没有在 else 语句中为您的变量设置值，这可能导致 SQL 无法插入您期望的内容。奇怪的是，我现在需要在作业中做同样的事情，这是我的解决方案：

CREATE TRIGGER instead_of_insert
ON Question4
INSTEAD OF INSERT AS
Declare @Username varchar(25) 
Declare @Question varchar(6)
Declare @Answer char(1)
Set @Username ='John'
IF (Select UserName from inserted) = @UserName
Begin
RAISERROR ('You have not paid up your fee', 10,1)
End
Else
Begin
Set @Username = (Select UserName from inserted)
Set @Question = (Select Question_ID from inserted)
Set @Answer = (Select Answer from inserted)
Insert into User_Responses 
Values
(@username, @Question, @Answer) 
End