<?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" >
<mapper namespace="cn.xdf.wlyy.jxdtest.dao.RoleDao">
<select >
SELECT * from role where id=#{value}
</select>
<select >
<!-- 模糊查询的两种方法 -->
<!-- SELECT * from role where name like '%${value}%'; -->
SELECT * from role where name like concat(concat('%',#{value}),'%');
</select>
<delete >
DELETE FROM role WHERE
id=#{value}
</delete>
<insert >
INSERT into
role(name,u_id) VALUES(#{name},#{u_id})
</insert>
<update >
UPDATE role set
name=#{name},u_id=#{u_id} where id =#{id}
</update>
<!--查询所有 resultMap返回结果 -->
<resultMap type="cn.xdf.wlyy.jxdtest.po.Role" >
select r.id,r.name,r.u_id
from role as r;
</select>
<!-- 多表联查 -->
<!-- 关联所需要的列 笛卡尔积 -->
<resultMap type="cn.xdf.wlyy.jxdtest.po.User" >
SELECT r.id r_id,u.id u_id,
r.name r_name,u.name u_name FROM role as r,user as u where r.u_id=u.id
</select>
<!-- 根据参数联查 -->
<resultMap type="cn.xdf.wlyy.jxdtest.po.Role" />
</collection> -->
<!--一对多嵌套方式column指向一的一方(唯一键) -->
<collection property="users" ofType="cn.xdf.wlyy.jxdtest.po.User"
column="r_id" select="getUsers"></collection>
<!--一对多实现的两种方式 -->
</resultMap>
<select >
<!-- 多对一查询 -->
<!-- select r.id r_id ,r.name r_name ,u.id u_id,u.name u_name from role
as r ,user as u where r.u_id=u.id and r.u_id=#{value} -->
<!-- 一对多查询 -->
select r.id r_id ,r.name r_name ,u.id u_id,u.name u_name from role as
r ,user as u where r.id=u.r_id and r.id=#{value}
</select>
<!-- 在做单表查询时候 字段为数据表中原有字段 -多对一 -->
<select >
select id ,name from user where r_id=#{value}
</select>
</mapper>