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  • mysql触发器——学习笔记及实验

    触发器是由事件来触发某个操作,事件包括insert,update,delect语句,重点学习创建,查看,删除。

    以实验为例

    1.在product表上分别创建AFTER INSERT、BEFORE UPDATE和BEFORE DELETE 3个触发器,  触发器的名称分别为product_af_insert、product_bf_update和Tproduct_bf_del。执行语句部分都是向operate表中插入操作方法和操作时间。

    mysql> create trigger product_af_insert after insert
        -> on product for each row
        -> insert into operate values(null,'insert product',now());
    Query OK, 0 rows affected
    
    mysql> create trigger product_bf_update before update
        -> on product for each row
        -> insert into operate values(null,'update product',now());
    Query OK, 0 rows affected
    
    mysql> create trigger product_bf_del before delete
        -> on product for each row
        -> insert into operate values(null,'delete product',now());
    Query OK, 0 rows affected

     

    2.查看product_bf_del触发器的基本结构。

    select * from information_schema.triggers where trigger_name='product_bf_del';

     

     

    3.product表分别执行如下INSERT、UPDATE和DELETE操作,分别查看operate表。

    INSERT INTO product VALUES(2, '止血灵','止血', '北京止血灵制药厂','北京市昌平区');

    UPDATE product SET address='天津市开发区' WHERE id=2;

    DELETE FROM product WHERE id=2;

    insert into product values(2,'止血灵','止血','北京止血灵制药厂','北京市昌平区');
    select * from product;
    select * from operate;
    
    update product set address='天津市开发区' where id=2;
    select * from product;
    select * from operate;
    
    delete from product where id=2;
    select * from product;
    select * from operate;

     

     

     

    4.删除product_bf_update触发器。

    drop trigger product_bf_update;

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  • 原文地址:https://www.cnblogs.com/liyanyinng/p/14051853.html
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