zoukankan      html  css  js  c++  java

  • mysql触发器的例子--插入前更新数据

    本文介绍下，一个mysql触发器的例子，在数据插入前更新相关内容，有需要的朋友参考下。

    mysql触发器的例子，如下：

    001 mysql> CREATE TABLE Employee(
    002     ->     id            int,
    003     ->     first_name    VARCHAR(15),
    004     ->     last_name     VARCHAR(15),
    005     ->     start_date    DATE,
    006     ->     end_date      DATE,
    007     ->     salary        FLOAT(8,2),
    008     ->     city          VARCHAR(10),
    009     ->     description   VARCHAR(15)
    010     -> );
    011 Query OK, 0 rows affected (0.03 sec)
    012  
    013 mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    014     ->              values (1,'Jason',    'Martin',  '19960725',  '20060725', 1234.56,'Toronto',  'Programmer');
    015 Query OK, 1 row affected (0.02 sec)
    016  
    017 mysql>
    018 mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    019     ->               values(2,'Alison',   'Mathews',  '19760321', '19860221', 6661.78,'Vancouver','Tester');
    020 Query OK, 1 row affected (0.00 sec)
    021  
    022 mysql>
    023 mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    024     ->               values(3,'James',    'Smith',    '19781212', '19900315', 6544.78,'Vancouver','Tester');
    025 Query OK, 1 row affected (0.00 sec)
    026  
    027 mysql>
    028 mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    029     ->               values(4,'Celia',    'Rice',     '19821024', '19990421', 2344.78,'Vancouver','Manager');
    030 Query OK, 1 row affected (0.00 sec)
    031  
    032 mysql>
    033 mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    034     ->               values(5,'Robert',   'Black',    '19840115', '19980808', 2334.78,'Vancouver','Tester');
    035 Query OK, 1 row affected (0.00 sec)
    036  
    037 mysql>
    038 mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    039     ->               values(6,'Linda',    'Green',    '19870730', '19960104', 4322.78,'New York',  'Tester');
    040 Query OK, 1 row affected (0.00 sec)
    041  
    042 mysql>
    043 mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    044     ->               values(7,'David',    'Larry',    '19901231', '19980212', 7897.78,'New York',  'Manager');
    045 Query OK, 1 row affected (0.00 sec)
    046  
    047 mysql>
    048 mysql> insert into Employee(id,first_name, last_name, start_date, end_Date,   salary,  City,       Description)
    049     ->               values(8,'James',    'Cat',     '19960917',  '20020415', 1232.78,'Vancouver', 'Tester');
    050 Query OK, 1 row affected (0.01 sec)
    051  
    052 mysql>
    053 mysql> select * from Employee;
    054 +------+------------+-----------+------------+------------+---------+-----------+-------------+
    055 | id   | first_name | last_name | start_date | end_date   | salary  | city      | description |
    056 +------+------------+-----------+------------+------------+---------+-----------+-------------+
    057 |    1 | Jason      | Martin    | 1996-07-25 | 2006-07-25 | 1234.56 | Toronto   | Programmer  |
    058 |    2 | Alison     | Mathews   | 1976-03-21 | 1986-02-21 | 6661.78 | Vancouver | Tester      |
    059 |    3 | James      | Smith     | 1978-12-12 | 1990-03-15 | 6544.78 | Vancouver | Tester      |
    060 |    4 | Celia      | Rice      | 1982-10-24 | 1999-04-21 | 2344.78 | Vancouver | Manager     |
    061 |    5 | Robert     | Black     | 1984-01-15 | 1998-08-08 | 2334.78 | Vancouver | Tester      |
    062 |    6 | Linda      | Green     | 1987-07-30 | 1996-01-04 | 4322.78 | New York  | Tester      |
    063 |    7 | David      | Larry     | 1990-12-31 | 1998-02-12 | 7897.78 | New York  | Manager     |
    064 |    8 | James      | Cat       | 1996-09-17 | 2002-04-15 | 1232.78 | Vancouver | Tester      |
    065 +------+------------+-----------+------------+------------+---------+-----------+-------------+
    066 8 rows in set (0.00 sec)
    067  
    068 mysql> DELIMITER //
    069 mysql>
    070 mysql> CREATE TRIGGER myTrigger BEFORE UPDATE ON employee //创建mysql触发器
    071     -> FOR EACH ROW
    072     -> BEGIN
    073     ->
    074     -> IF NEW.id > 5 THEN
    075     ->     SET NEW.first_name = NEW.first_name+ " *";
    076     -> END IF;
    077     ->
    078     -> IF NEW.salary IS NULL OR NEW.salary = 0 THEN
    079     ->         SET NEW.salary = 100;
    080     -> ELSE
    081     ->         SET NEW.salary = NEW.salary + 100;
    082     -> END IF;
    083     ->
    084     -> END
    085     ->
    086     -> //
    087 Query OK, 0 rows affected (0.00 sec)
    088  
    089 mysql> DELIMITER ;
    090 mysql>
    091 mysql> update employee set id = 6, first_name= 'new', salary = null; //更新数据
    092 Query OK, 8 rows affected, 8 warnings (0.00 sec)
    093 Rows matched: 8  Changed: 8  Warnings: 0
    --// www.jbxue.com
    095 mysql>
    096 mysql> select * from employee;
    097 +------+------------+-----------+------------+------------+--------+-----------+-------------+
    098 | id   | first_name | last_name | start_date | end_date   | salary | city      | description |
    099 +------+------------+-----------+------------+------------+--------+-----------+-------------+
    100 |    6 | 0          | Martin    | 1996-07-25 | 2006-07-25 | 100.00 | Toronto   | Programmer  |
    101 |    6 | 0          | Mathews   | 1976-03-21 | 1986-02-21 | 100.00 | Vancouver | Tester      |
    102 |    6 | 0          | Smith     | 1978-12-12 | 1990-03-15 | 100.00 | Vancouver | Tester      |
    103 |    6 | 0          | Rice      | 1982-10-24 | 1999-04-21 | 100.00 | Vancouver | Manager     |
    104 |    6 | 0          | Black     | 1984-01-15 | 1998-08-08 | 100.00 | Vancouver | Tester      |
    105 |    6 | 0          | Green     | 1987-07-30 | 1996-01-04 | 100.00 | New York  | Tester      |
    106 |    6 | 0          | Larry     | 1990-12-31 | 1998-02-12 | 100.00 | New York  | Manager     |
    107 |    6 | 0          | Cat       | 1996-09-17 | 2002-04-15 | 100.00 | Vancouver | Tester      |
    108 +------+------------+-----------+------------+------------+--------+-----------+-------------+
    109 8 rows in set (0.00 sec)
    110  
    111 mysql>
    112 mysql> update employee set id = 7, first_name= 'new', salary = 100; //更新数据
    113 Query OK, 8 rows affected, 8 warnings (0.00 sec)
    114 Rows matched: 8  Changed: 8  Warnings: 0
    115  
    116 mysql>
    117 mysql> select * from employee;
    118 +------+------------+-----------+------------+------------+--------+-----------+-------------+
    119 | id   | first_name | last_name | start_date | end_date   | salary | city      | description |
    120 +------+------------+-----------+------------+------------+--------+-----------+-------------+
    121 |    7 | 0          | Martin    | 1996-07-25 | 2006-07-25 | 200.00 | Toronto   | Programmer  |
    122 |    7 | 0          | Mathews   | 1976-03-21 | 1986-02-21 | 200.00 | Vancouver | Tester      |
    123 |    7 | 0          | Smith     | 1978-12-12 | 1990-03-15 | 200.00 | Vancouver | Tester      |
    124 |    7 | 0          | Rice      | 1982-10-24 | 1999-04-21 | 200.00 | Vancouver | Manager     |
    125 |    7 | 0          | Black     | 1984-01-15 | 1998-08-08 | 200.00 | Vancouver | Tester      |
    126 |    7 | 0          | Green     | 1987-07-30 | 1996-01-04 | 200.00 | New York  | Tester      |
    127 |    7 | 0          | Larry     | 1990-12-31 | 1998-02-12 | 200.00 | New York  | Manager     |
    128 |    7 | 0          | Cat       | 1996-09-17 | 2002-04-15 | 200.00 | Vancouver | Tester      |
    129 +------+------------+-----------+------------+------------+--------+-----------+-------------+
    130 8 rows in set (0.00 sec)
    131  
    132 mysql> drop table Employee;
    133 Query OK, 0 rows affected (0.02 sec)
    本文原始链接：http://www.jbxue.com/db/11615.html
  • 相关阅读:
    Vim step by step
    Ubuntu解压命令全览
    这样才能使本地Mysql服务允许被外部主机连接(两步)
    [Python] logging.logger
    Python Selenium
    MySQL中char、varchar和text的区别
    Way to MongoDB
    Python误区之strip,lstrip,rstrip
    Android Studio Tips
    Way to tmux
  • 原文地址：https://www.cnblogs.com/linuxnotes/p/3393565.html
Copyright © 2011-2022 走看看