MyBatis一对一关联

实例： 用户和详情

用户信息表：

create table users(
user_id int primary key auto_increment,
user_name varchar(20) not null unique,
user_pwd varchar(20) not null,
user_realname varchar(32) not null,
user_img varchar(100)
);

用户详情表
create table details(
detail_id int primary key auto_increment,
user_addr varchar(50) not null,
user_tel varchar(11) not null,
user_desc varchar(200),
uid int not null unique,
constraint FX_USER foreign key(uid) references users(user_id)
);

package com.ccl.pojo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;


@Data
@NoArgsConstructor
@AllArgsConstructor
@ToString
public class Users {
    private Integer user_id;
    private String user_name;
    private String user_pwd;
    private String user_realname;
    private String user_img;
}

package com.ccl.pojo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;


@Data
@NoArgsConstructor
@AllArgsConstructor
@ToString
public class Details {
    private Integer detail_id;
    private String user_addr;
    private String user_desc;
    private Integer uid;
}

public interface DetailDao {
    public int insertDetail(Detail detail);
}

public interface UserDao {
    //添加
    public int insertUser(User users);
    //查询单个用户
    public User queryUser(String userName);
}

    
        insert into users (user_name,user_pwd,user_realname,user_img)   values(#{user_name},#{user_pwd},#{user_realname},#{user_img})
    
    
        user_id,user_name,user_pwd,user_realname,user_img
    


    
        
        
        
        
        
    
    
        select user_id,user_name,user_pwd,user_realname,user_img
        from users where user_name=#{userName}
    

    
        insert  into details (user_addr,user_tel,user_desc,uid)
        values(#{user_addr},#{user_tel},#{user_desc},#{uid})
    

package com.ccl.dao;


import com.ccl.Utils.MyBatisUtil;
import com.ccl.pojo.Detail;
import com.ccl.pojo.User;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;


public class UserDaoTest {
    @Test
    public void testInsertUser(){
        //用户注册提交的基本信息和详情到Servlet,Servlet接收注册信息封装到Detail和User中
        User user = new User(0,"赵六","123123","赵六","03.jpg");
        Detail detail = new Detail(0,"湖北省武汉市","14334123126","有个性才签名",0);

        SqlSession sqlSession = MyBatisUtil.getSqlSession();
        int i = 0;
        int i1 = 0;
        try {
            UserDao userDao = sqlSession.getMapper(UserDao.class);
            i = userDao.insertUser(user);
            detail.setUid(user.getUser_id());

            DetailDao detailDao = sqlSession.getMapper(DetailDao.class);
            i1 = detailDao.insertDetail(detail);

            System.out.println(i);
            System.out.println(i1);

            sqlSession.commit();
        } catch (Exception e) {
            sqlSession.rollback();
        }

    }

    @Test
    public void testQuerUser(){
        UserDao userDao = MyBatisUtil.getMapper(UserDao.class);
        User user = userDao.queryUser("王五");
        System.out.println(user);
    }
}

在查询用户的同时关联查询出与之对应的详情表

• 实体

    
    
    
    
    
    
    
    
    



    select user_id,user_name,user_pwd,user_realname,user_img,detail_id,user_addr,user_tel,user_desc
    from users u
    inner join details d
    on u.user_id=d.uid
    where u.user_name=#{userName}

 
子查询（第二种方案）
 
 
        
        
        
        
        

        
    

    
        select user_id,user_name,user_pwd,user_realname,user_img
        from users
        where user_name=#{userName}
    

    
    
    
    


    select detail_id,user_addr,user_tel,user_desc,uid
    from details where uid=#{uid}