How to set a composite primary key for a table in MySQL?

#Mysql sometimes encounters multiple fields to represent the uniqueness of data, so a composite primary key will be used here.

Recommended related mysql video tutorials: "mysql tutorial"

##1. Write the sql code to create the table ;

2. Set the joint primary key;

##3. Execute the code and find an error;

4. Solution: Increment the id Add UNIQUE unique index to the column;

##5. The code is executed successfully;

#6. The joint primary key is created successfully.

7.SQL sample code:

USE test
CREATE TABLE `test_table` (
  `id` INT(11) NOT NULL AUTO_INCREMENT UNIQUE COMMENT '自增',
  `realName` VARCHAR(50) CHARACTER SET gbk DEFAULT NULL COMMENT '真实姓名',
  `area_id` VARCHAR(50) CHARACTER SET gbk DEFAULT NULL COMMENT '地区编号',
  `enter_time` INT(11) DEFAULT NULL COMMENT '录入时间',
  `mark` VARCHAR(60) CHARACTER SET gbk DEFAULT NULL COMMENT '备注',
  PRIMARY KEY (`realName`,`area_id`)
) ENGINE=MYISAM AUTO_INCREMENT=1133 DEFAULT CHARSET=gbk;

The above is the detailed content of How to set a composite primary key for a table in MySQL?. For more information, please follow other related articles on the PHP Chinese website!