Java All parts of a PRIMARY KEY must be NOT NULL；if you need NULL in a key,use UNIQUE instead问题解决

约定不等于承诺〃 2022-09-12 06:42 141阅读 0赞

### 问题描述： ###

Cause: java.sql.SQLSyntaxErrorException: All parts of a PRIMARY KEY must be NOT NULL; if you need NULL in a key, use UNIQUE instead

### 问题分析： ###

1、设为主键的字段设置了可以为null。

CREATE TABLE users(
                `username` varchar(20) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT '用户名',
                `password` varchar(20) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '密码',
                PRIMARY KEY (`user_name`, `password`) USING BTREE
                    USING BTREE
            ) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = DYNAMIC;

解决办法：设为主键的字段设置为not null即可。

CREATE TABLE users(
                `username` varchar(20) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT '用户名',
                `password` varchar(20) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT '密码',
                PRIMARY KEY (`user_name`, `password`) USING BTREE
                    USING BTREE
            ) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = DYNAMIC;