Question

我需要创建触发器，该触发器将检查表中是否存在具有相同时间和相同剧院ID的值

CREATE TRIGGER trCheckSameTime
ON dbo.Poster
FOR INSERT,UPDATE
AS
    IF EXISTS(SELECT P.Id_Poster
              FROM Poster P, inserted I
              WHERE P.Date = I.Date AND P.Id_Theater = I.Id_Theater)
    BEGIN 
        ROLLBACK TRANSACTION
        RAISERROR('There can''t be two spectacles at the same time in the same theater', 16, 10)
    END

我正在尝试使用它，所以当我输入

时就想要它

INSERT INTO Poster
VALUES (1,4,1,'20190420 16:00:00')
INSERT INTO Poster
VALUES (1,4,1,'20190420 16:00:00')

要触发它禁止这样做，但是此触发器禁止在表中输入任何数据。

表中的第三个值是Theater_id，第四个值是日期，

Answer 1

您需要先检查数据插入为

*s2 == 0

您还可以创建CREATE TRIGGER trCheckSameTime ON dbo.Poster INSTEAD OF INSERT, UPDATE AS IF NOT EXISTS( SELECT 1 FROM dbo.Poster P INNER JOIN INSERTED I ON P.Id_Theater = I.Id_Theater AND P.[Date] = I.[Date] ) BEGIN INSERT INTO dbo.Poster(<Columns Here>) SELECT <Columns Here> FROM INSERTED; END ELSE BEGIN RAISERROR('There can''t be two spectacles at the same time in the same theater', 16, 10) END，这是解决问题的更好方法。

constraint

比较插入的日期与触发器中现有的日期

1 个答案: