Mybatis 一对一 关系查询（分步查询）

• 一、创建表
• 二、分步查询

学生表：

教师表：

SELECt s.id,s.Sname,t.Tname FROM student s,teacher t where s.t_id = t.id

①：设置实体类

public class Student {

    private Integer id;
    private String Sname;
    private String sex;
    private Integer age;
    private Integer t_id;
    //这个是重点
    private Teacher teacher;
}

public class Teacher {
    private Integer id;
    private String Tname;
}

②：查询语句；在studentMapper.xml当中设置分步查询

    select * from student;


    
    
    
    
    
    

③配置studentMapper
Student getStudent();
④在TeacherMapper.xml当中设置关于教师的查询

    select  * from  teacher where id = #{t_id};    id}; 可以写任何东西，因为会自动匹配 t_id -->

⑤配置TeacherMapper
Teacher getTeacher(Integer id);

测试：