<!-- <resultMap type="employee" id="emplist"> <id property="ids" column="IDS"/> <result property="ename" column="ENAME"/> <result property="esex" column="ESEX"/> <result property="birthday" column="BIRTHDAY"/> <result property="address" column="ADDRESS"/> <result property="dept.id" column="ID"/> <result property="dept.dname" column="DNAME"/> <result property="dept.createtime" column="CREATETIME"/> </resultMap> -->
这个是级联查询 一次性把两个表的内容都累出来
<!--<resultMap type="employee" id="emplist"> <id property="ids" column="IDS"/> <result property="ename" column="ENAME"/> <result property="esex" column="ESEX"/> <result property="birthday" column="BIRTHDAY"/> <result property="address" column="ADDRESS"/> <association property="dept" resultMap="deptlist"></association> </resultMap> <resultMap type="dept" id="deptlist"> <result property="id" column="ID"/> <result property="dname" column="DNAME"/> <result property="createtime" column="CREATETIME"/> </resultMap> -->
<!-- <resultMap type="employee" id="emplists"> <association property="dept" column="deptid" select="mapper.DeptMapper.selectDept"></association> </resultMap> <select id="selectAllEmployee" resultMap="emplists" > SELECT * FROM EMPLOYEE E JOIN DEPT D ON E.DEPTID=D.ID </select> --> <resultMap type="employee" id="myemp"> <id column="ids" property="ids"/> <result column="ename" property="ename" /> <result column="esex" property="esex" /> <result column="birthday" property="birthday"/> <result column="address" property="address"/> <association property="dept" column="deptid" select="mapper.DeptMapper.selectDept"></association> </resultMap> <select id="selectEmployee" resultMap="myemp"> select * from employee e where e.ids=#{id} </select>
这两个都是分布查询 多对一也是这样的 只是association 换成collection
<resultMap type="dept" id="mydept"> <id property="id" column="id"/> <result property="dname" column="dname"/> <result property="createtime" column="createtime"/> <collection property="list" column="id" select="mapper.EmployeeMapper.selectOneEmployee"></collection> </resultMap> <select id="selectOneDept" parameterType="Integer" resultMap="mydept"> select * from dept d where d.id=#{id} </select>
多对一查询
联合查询一般用分布查询 resultmap标签中 type类型就是想要查询的类型 id随便写 是resultmap的唯一标识,collection标签中 property 属性指定的是联合查询的是哪个 column传入的指定的值 工select查询
resultmap 是制定封装规则 所以定义哪个对象的封装规则 那么 这个标签的type属性就写哪个
时间: 2024-10-30 02:13:02