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：

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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

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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)

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