mybatis 一对一对多多对多对多

Posted 2020-10-02 liduanwen

本项目是  框架架构是 springboot+mybatis

添加maven依赖

<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>${mybatis-spring-boot.version}</version>
</dependency>


在 application.properties 配置

#为实体对象所在的包，跟数据库表一一对应
mybatis.typeAliasesPackage=com.exer.demo.entity
#mapper文件的位置
mybatis.mapperLocations=classpath:mapper/*.xml




数据库
DROP TABLE IF EXISTS `student`;
CREATE TABLE `student` (
  `id` bigint(30) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) DEFAULT NULL,
  `age` int(30) DEFAULT NULL,
  `teacher_id` bigint(30) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of student
-- ----------------------------
INSERT INTO `student` VALUES (\'1\', \'weww\', \'10\', \'1\');
INSERT INTO `student` VALUES (\'2\', \'asdd\', \'12\', \'1\');

-- ----------------------------
-- Table structure for teacher
-- ----------------------------
DROP TABLE IF EXISTS `teacher`;
CREATE TABLE `teacher` (
  `id` bigint(30) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) DEFAULT NULL,
  `age` int(30) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of teacher
-- ----------------------------
INSERT INTO `teacher` VALUES (\'1\', \'tytt\', \'32\');
INSERT INTO `teacher` VALUES (\'2\', \'ytyty\', \'24\');

-- ----------------------------
-- Table structure for user
-- ----------------------------
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user` (
  `id` int(11) NOT NULL COMMENT \'主键\',
  `name` varchar(64) NOT NULL COMMENT \'姓名\',
  `birthday` date DEFAULT NULL COMMENT \'生日\',
  `address` varchar(256) DEFAULT NULL COMMENT \'地址\',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of user
-- ----------------------------
INSERT INTO `user` VALUES (\'1\', \'小明\', \'2017-08-12\', \'北京市丰台区科怡路\');
INSERT INTO `user` VALUES (\'2\', \'小刚\', \'2017-08-12\', \'北京市海淀区\');

-- ----------------------------
-- Table structure for user_device
-- ----------------------------
DROP TABLE IF EXISTS `user_device`;
CREATE TABLE `user_device` (
  `id` int(11) NOT NULL COMMENT \'主键\',
  `user_device_name` varchar(64) NOT NULL COMMENT \'设备名称\',
  `user_id` int(11) DEFAULT NULL COMMENT \'用户ID\',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of user_device
-- ----------------------------
INSERT INTO `user_device` VALUES (\'1\', \'安卓\', \'1\');
INSERT INTO `user_device` VALUES (\'2\', \'ios\', \'1\');