标签:name 一对一 mybatie teacher student tid 一对 id select
association是用于一对一和多对一,而collection是用于一对多的关系
<!--按照结果嵌套查询-->
<select id="getTeacher" resultMap="TeacherStudent">
select t.name tname,t.id tid,s.name sname ,s.id sid
from teacher t left join student s on t.id=s.tid
where t.id=#{tid}
</select>
<resultMap id="TeacherStudent" type="com.wyl.pojo.Teacher">
<result property="name" column="tname"/>
<result property="id" column="tid"/>
<collection property="student" ofType="com.wyl.pojo.Student" javaType="ArrayList">
<result property="id" column="sid"/>
<result property="name" column="sname"/>
<result property="tid" column="tid"/>
</collection>
</resultMap>
<select id="getTeacher2" resultMap="TeacherStudent2">
select * from teacher where id=#{tid}
</select>
<resultMap id="TeacherStudent2" type="com.wyl.pojo.Teacher">
<collection property="student" javaType="ArrayList" ofType="com.wyl.pojo.Student" select="getStudent" column="id">
</collection>
</resultMap>
<select id="getStudent" resultType="com.wyl.pojo.Student">
select * from student where tid=#{tid}
</select>
================================================
<!-- 方式1 按照查询嵌套处理-->
<resultMap id="StudentTeacher" type="com.wyl.pojo.Student">
<result property="id" column="id"/>
<result property="name" column="name"/>
<!--复杂的属性需要单独处理-->
<!--对象 association 集合clooection-->
<!--property 写student 中的 teacher column对应数据库字段-->
<association property="teacher" column="tid" javaType="com.wyl.pojo.Teacher" select="getTeacher"/>
</resultMap>
<select id="getStudent" resultMap="StudentTeacher">
select * from student
</select>
<select id="getTeacher" resultType="com.wyl.pojo.Teacher">
select * from Teacher
</select>
<!--方式2 按照结果嵌套处理-->
<resultMap id="StudentTeacher2" type="com.wyl.pojo.Student">
<result property="id" column="sid"/>
<result property="name" column="sname"/>
<association property="teacher" javaType="com.wyl.pojo.Teacher">
<result property="name" column="tname"/>
<result property="id" column="tid"/>
</association>
</resultMap>
<select id="getStudent2" resultMap="StudentTeacher2">
select s.id as sid,s.name as sname,t.name as tname,t.id as tid
from student s left join teacher t
on s.tid=t.id
</select>
标签:name,一对一,mybatie,teacher,student,tid,一对,id,select 来源: https://blog.csdn.net/weixin_44476613/article/details/121190434
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