mysql 給表添加惟一約束、聯合惟一約束，指定惟一約束的名字

表結構

 

FIELD          TYPE          COLLATION       NULL    KEY     DEFAULT  Extra           PRIVILEGES            COMMENT
-------------  ------------  --------------  ------  ------  -------  --------------  --------------------  -------
id             BIGINT(20)    (NULL)          NO      PRI     (NULL)   AUTO_INCREMENT  SELECT,INSERT,UPDATE
resource_name  VARCHAR(128)  gbk_chinese_ci  YES             (NULL)                   SELECT,INSERT,UPDATE
resource_type  TINYINT(4)    (NULL)          YES             (NULL)                   SELECT,INSERT,UPDATE

給resource_name和resource_type添加聯合惟一約束

 

 

ALTER TABLE jw_resource
ADD UNIQUE KEY(resource_name, resource_type);

結果 show create table jw_resource;

 

 

CREATE TABLE `jw_resource` (
  `id` BIGINT(20) NOT NULL AUTO_INCREMENT,
  `resource_name` VARCHAR(128) DEFAULT NULL,
  `resource_type` TINYINT(4) DEFAULT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `resource_name` (`resource_name`,`resource_type`)
) ENGINE=INNODB AUTO_INCREMENT=2 DEFAULT CHARSET=gbk

 

刪除惟一約束

 

ALTER TABLE jw_role DROP INDEX resource_name;

 

增長一個惟一約束，而且給惟一約束起名字？

原表結構：

 

mysql> show create table test_table;
+------------+--------------------------------------------------------------------------------------------------------------------------------------------
---------------------------------+
| Table      | Create Table
                                 |
+------------+--------------------------------------------------------------------------------------------------------------------------------------------
---------------------------------+
| test_table | CREATE TABLE `test_table` (
  `id` int(50) NOT NULL AUTO_INCREMENT,
  `kk` varchar(30) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=latin1 |
+------------+--------------------------------------------------------------------------------------------------------------------------------------------
---------------------------------+
1 row in set (0.00 sec)

增長惟一約束的語句，給惟一約束起名叫作 kk_uq：

 

 

mysql> alter table test_table add unique key `kk_uq` ( kk);

查看結果

 

 

mysql> show create table test_table;
+------------+--------------------------------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------+
| Table      | Create Table
                                                              |
+------------+--------------------------------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------+
| test_table | CREATE TABLE `test_table` (
  `id` int(50) NOT NULL AUTO_INCREMENT,
  `kk` varchar(30) DEFAULT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `kk_uq` (`kk`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=latin1 |
+------------+--------------------------------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------+
1 row in set (0.00 sec)