在多个表视图上插入带有检查选项的触发器

Question

我在多个 table 视图上触发时遇到问题。

让我解释一下：我有 2 个带主键的数据 table 和具有多对多关系的 table 事件。

CREATE TABLE Club
(
    name_of_club varchar(50) PRIMARY KEY,
    adress varchar(50) NOT NULL
)

CREATE TABLE Band
(
    name_of_band varchar(50) PRIMARY KEY,
    members int NOT NULL
)


CREATE TABLE Event
(
    name_of_club varchar(50) NOT NULL,
    name_of_band varchar(50) NOT NULL,
        data date NOT NULL,
    CONSTRAINT PK_Event PRIMARY KEY
    (
        name_of_club,
        name_of_band
    ),
    FOREIGN KEY (name_of_club) REFERENCES Club (name_of_club),
    FOREIGN KEY (name_of_band) REFERENCES Band (name_of_band)
)

现在我可以添加一些值了：

insert into Club (name_of_club, adress)
       values
       ('Big London Club', 'Londyn, Baker Street 12'),
       ('Espana Time', 'Barcelona, Diego 15'),
       ('Wwa', 'Warszawa, Sezonowa 82/14'),
       ('Szwalnia', 'Łódź, Piotrkowska 20/2');

insert into Band (name_of_band, members)
       values
       ('Arctic Monkeys', 5),
       ('Random Guys', 3),
       ('TILT', 10),
       ('Joke Time', 2);



insert into Event (name_of_club, name_of_band, data)
           values
           ('Big London Club', 'Arctic Monkeys', '2015-01-25'),
           ('Wwa', 'TILT', '2015-01-28'),
           ('Szwalnia', 'Joke Time', '2015-02-10');

让我们创建视图：

CREATE VIEW Events AS

SELECT Club.name_of_club, adress, Band.name_of_band, members, data
FROM Event
JOIN Club ON Club.name_of_club = Event.name_of_club
JOIN Band ON Band.name_of_band = Event.name_of_band

现在我必须为 INSERT 操作创建触发器。

1 * 向视图中插入一行时，我需要检查一行是否存在：

YES -> 显示错误
否 -> 转到第 2 点

2 * 检查插入时是否有指定名称的俱乐部和乐队。

如果是，检查信息是否更正并转到 3* 。
如果有问题->显示错误。

3 * 当行包含俱乐部的数据且乐队不在 table，妆底tables。尾妆活动table 代表多对多关系。现在应该更好了。

编辑：触发点

Answer 1

可以使用INSTEAD OF TRIGGER来完成，触发器应该是这样的：

CREATE TRIGGER InsteadOfEventInsert ON Events INSTEAD OF INSERT
AS
BEGIN
    DECLARE @name_of_club VARCHAR(50),
            @name_of_band VARCHAR(50),
            @data DATE,
            @members int

    SELECT  @name_of_club = name_of_club,
            @name_of_band = name_of_band,
            @data = data,
            @members = members
    FROM INSERTED

    IF NOT EXISTS(  SELECT  1 
                    FROM    Events 
                    WHERE   name_of_club = @name_of_club 
                    AND     name_of_band = @name_of_band 
                    AND     data = @data
                )
    BEGIN
        IF NOT EXISTS(SELECT 1 FROM Club WHERE name_of_club = @name_of_club)
            INSERT INTO Club VALUES(@name_of_club, @members)

        IF NOT EXISTS(SELECT 1 FROM Band WHERE name_of_band = @name_of_band)
            INSERT INTO Band VALUES(@name_of_band, @members)

        INSERT INTO [Event] SELECT name_of_club, name_of_band, data FROM INSERTED
    END
END

我建议只为俱乐部和乐队添加一个 INT 标识列，而不是将名称作为主键。

Answer 2

示例插入：

INSERT INTO Events values ('Test Club', 'Test Adress', 'Test Band', 5, '2015-01-01')

触发器：

CREATE TRIGGER InsteadOfEventInsert ON Events INSTEAD OF INSERT
AS
BEGIN
    DECLARE @name_of_club VARCHAR(50),
            @adress varchar(50),
            @name_of_band VARCHAR(50),
            @members int,
            @data date

    SELECT  @name_of_club = name_of_club,
            @adress = adress,
            @name_of_band = name_of_band,
            @members = members,
            @data = data
    FROM INSERTED

    IF NOT EXISTS(  SELECT  1 
                    FROM    Events 
                    WHERE   name_of_club = @name_of_club 
                    AND     adress = @adress
                    AND     name_of_band = @name_of_band 
                    AND     data = @data
                )

    BEGIN
        IF NOT EXISTS(SELECT 1 FROM Club WHERE name_of_club = @name_of_club)
        INSERT INTO Club VALUES(@name_of_club, @adress)

        IF NOT EXISTS(SELECT 1 FROM Band WHERE name_of_band = @name_of_band)
        INSERT INTO Band VALUES(@name_of_band, @members)
    END
    INSERT INTO [Event] SELECT name_of_club, name_of_band, data FROM INSERTED
END

它应该看起来像这样？

编辑：有效 ;)

在多个表视图上插入带有检查选项的触发器

Insert Trigger with check option on multiple tables view

sql

tsql

sql-server