标签:name 处理 student tid where id select
- 按照查询嵌套处理
点击查看代码
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.kuang.dao.StudentMapper">
<!--
思路:
1.查询出所有学生信息
2.根据查询出来的tid,寻找对应的老师
-->
<select id="getStudent" resultMap="StudentTeacher">
select * from student
</select>
<resultMap id="StudentTeacher" type="Student">
<result property="id" column="id"/>
<result property="name" column="name"/>
<!-- 复杂对象需要单独处理 对象:association 集合 :collection -->
<association property="teacher" column="tid" javaType="Teacher" select="getTeacher"/>
</resultMap>
<select id="getTeacher" resultType="Teacher">
select * from teacher where id=#{id}
</select>
</mapper>
- 按照结果嵌套处理
<select id="getStudent2" resultMap="StudentTeacher2">
select s.id sid, s.name sname, t.name tname
from student s, teacher t
where s.tid = t.id
</select>
<resultMap id="StudentTeacher2" type="Student">
<result property="id" column="sid"/>
<result property="name" column="sname"/>
<association property="teacher" javaType="Teacher">
<result property="name" column="tname"/>
</association>
</resultMap>
按照结果嵌套处理
<select id="getTeacher" resultMap="TeacherStudent">
select s.id sid, s.name sname, t.id tid , t.name tname
from student s, teacher t
where s.tid = t.id and t.id = #{tid}
</select>
<resultMap id="TeacherStudent" type="Teacher">
<result property="id" column="tid"/>
<result property="name" column="tname"/>
<collection property="students" ofType="Student">
<result property="id" column="sid"/>
<result property="name" column="sname"/>
<result property="tid" column="tid"/>
</collection>
</resultMap>
按照查询嵌套处理
<select id="getTeacher2" resultMap="TeacherStudent2">
select * from mybatis.teacher where id =#{tid};
</select>
<resultMap id="TeacherStudent2" type="Teacher">
<collection property="students" javaType="Arraylist" ofType="Student" select="getStudentByTeacherId" column="id"/>
</resultMap>
<select id="getStudentByTeacherId" resultType="Student">
select * from mybatis.student where tid =#{tid};
</select>
标签:name,处理,student,tid,where,id,select 来源: https://www.cnblogs.com/ahhh7931/p/16558257.html
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