MyBatis多对多（预习）

循环添加中间表记录

<insertid="addcenter">

 insert into t_teacher_student(teacherId,studentId) values

 <foreach collection="students" separator=","item="studentId">

  (#{id},#{studentId})

  </foreach>

  </insert>

删除中间表相关记录，再添加中间表记录

<updateid="update">

  update t_teacher t sett.teacherName=#{teacherName} where t.id=#{id};

  delete from t_teacher_student whereteacherId=#{id};

  

  insert intot_teacher_student(teacherId,studentId) values

 <foreach collection="stuIds"conjunction="," item="stuId">

 (#{id},#{stuId})

 </iterate>

  </update>