Add a unique constraint to a table using myql

Table Structure

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 

Add a unique constraint for resource_name and resource_type

ALTER TABLE jw_resourceADD UNIQUE KEY(resource_name, resource_type);

Result: Show create table resource_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