<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<!-- namespace表示命名空间  保证它是唯一   cn.itsource.mybatis.dao.impl.ProductDaoImpl + id="getUserById"-->
<mapper namespace="_04_onetomany.DeptMapper">
    <!-- 一对多 嵌套结果 -->
    <select id="query01" resultMap="deptMp">
        select d.id,d.name,e.id eid,e.name ename  from dept d left join employee e
        on d.id = e.dept_id
    </select>
    <resultMap id="deptMp" type="_04_onetomany.Dept">
            <id column="id" property="id"></id>
            <result column="name" property="name"></result>
            <!--property 类里面属性 javaType集合属性 ofType集合里面类型-->
            <collection property="employees" javaType="arraylist" ofType="_04_onetomany.Employee">
                <id column="eid" property="id"></id>
                <result column="ename" property="name"></result>
            </collection>
    </resultMap>

    <!-- 一对多嵌套查询 -->
    <select id="query02" resultMap="deptMp1">
        select * from dept
    </select>
    <resultMap id="deptMp1" type="_04_onetomany.Dept">
        <id column="id" property="id"></id>
        <result column="name" property="name"></result>
        <!--property 类里面属性 javaType集合属性 ofType集合里面类型-->
        <collection property="employees" column="id" select="getEmployeeByDeptId">
        </collection>
    </resultMap>

    <select id="getEmployeeByDeptId" parameterType="long" resultType="_04_onetomany.Employee">
         select * from employee where dept_id =#{id}
    </select>



</mapper>