mysql触发器 实例_mysql触发器的三个例子
发布时间：2023-12-22 03:03:10 所属栏目：MySql 来源：DaWei
导读： 本节内容：
mysql触发器实例
例1mysql触发器，
复制代码 代码示例:
delimiter //
create trigger InsertUser
before insert on user
for each row
Begin
insert
mysql触发器实例
例1mysql触发器，
复制代码 代码示例:
delimiter //
create trigger InsertUser
before insert on user
for each row
Begin
insert
|
本节内容： mysql触发器实例 例1mysql触发器， 复制代码 代码示例: delimiter // create trigger InsertUser before insert on user for each row Begin insert into user_group(uid,gid) values(new.uid,'group4444444444'); end;// delimiter ; 例2， 复制代码 代码示例: delimiter // create trigger InsertUser before insert on user for each row Begin IF new.Type=2 then insert into user_group(uid,gid) values(new.uid,'group4444444444'); else insert into user_group(uid,gid) values(new.uid,'group55555555555') END IF; end;// delimiter ; 例3， 复制代码 代码示例: delimiter // create trigger InsertUser before insert on user for each row Begin IF new.type=1 then insert into user_group(uid,gid) values(new.uid,'578d3369633b47bd9c1fe8bf905cbfb1'); END IF; IF new.type=2 then insert into user_group(uid,gid) values(new.uid,'387bcd57fc5a4c3c9de83ee210fef661'); END IF; end;// delimiter ; mySql触发器实例 在mysql中，使用触发器能进行一些约束。 例子，当Student表的StudentID列被发生更改时,BorrowStudent表的StudentID列也跟着更改.如果Student表删除某记录,BorrowStudent也删除对应StudentID的记录. 复制代码 代码示例: /*先删除将要创建而存在的表*/ drop table if exists Student; drop table if exists BorrowStudent; /*创建表*/ create table Student( StudentID int not null primary key, StudentName varchar(30) not null, StudentSex enum('m','f') default 'm' )engine=myisam; create table BorrowStudent( BorrowRecord int not null auto_increment primary key, StudentID int not null, BorrorDate date, ReturnDate date, foreign key(StudentID) references Student(StudentID) )engine=myisam; /*插入记录*/ insert into Student values(1235412,'java','m'); insert into Student values(3214562,'jiajia','m'); insert into Student values(5441253,'purana','f'); insert into BorrowStudent(StudentID,BorrorDate,ReturnDate) values(1235412,'2007-01-01','2007-01-07'); insert into BorrowStudent(StudentID,BorrorDate,ReturnDate) values(3214562,'2007-01-01','2007-01-07'); insert into BorrowStudent(StudentID,BorrorDate,ReturnDate) values(5441253,'2007-01-01','2007-01-07'); /*创建触发器*/ delimiter $$ drop trigger if exists tduStudent$$ drop trigger if exists tddStudent$$ create trigger tduStudent before update on Student for each row begin if new.StudentID!=old.StudentID then update BorrowStudent set BorrowStudent.StudentID=new.StudentID where BorrowStudent.StudentID=old.StudentID; end if; end$$ create trigger tddStudent before delete on Student for each row begin delete from BorrowStudent where BorrowStudent.StudentID=old.StudentID; end$$ delimiter ; （编辑：商洛站长网） 【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容! |
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