触发器(trigger)用于监视某种情况并触发某种操作,它是与表时间相关的特殊存储过程。它的执行不是由程序调用,而是由事件来触发的。它只会在对某张表进行 insert、delete 和 update 操作时执行。语法如下:
create trigger trigger_name trigger_time trigger_event ON table_name FOR EACH ROW trigger_stmt
参数:
create table users(
id int not null auto_increment primary key,
name varchar(30),
email varchar(30)
);
create table emails(
id int not null auto_increment primary key,
email varchar(30),
content text.
send_datetime datetime
);
delimiter //
create trigger add_email after insert on users for each row
begin
insert into emails(email,content,send_datetime) values (NEW.email,'hello' ,now());
end
//
delimiter ;