从MySql到Sql Server的删除触发器之后进行转换

Question

如何为MS SQL Server编写this触发器？

MySql版本：

CREATE TRIGGER log_patron_delete AFTER DELETE on patrons
FOR EACH ROW
BEGIN
DELETE FROM patron_info
    WHERE patron_info.pid = old.id;
END

Sql server版本：

CREATE TRIGGER log_patron_delete ON patrons AFTER DELETE
AS
BEGIN
DELETE FROM patron_info WHERE patron_info.pid = old.id;
END

问题：old.id适用于MySql，但不适用于MS SQL Server

Answer 1

这不是触发器的工作，它是外键约束的工作。 您应该在patrons表和patron_info表之间创建一个外键，并使用选项delete cascade创建它。

ALTER TABLE patron_info 
ADD CONSTRAINT FK_patron_info_patrons FOREIGN KEY (pid) 
    REFERENCES patrons(id) 
    ON DELETE CASCADE

这样，你不能在patron_info中有任何与patrons表无关的行，一旦你从patrons表中删除了一行，patron_info中的相应行就会被自动删除。