mybatis 一對一 一對多

數據庫多表一對一查詢

 <!--定義封裝account和user-->
    <resultMap id="accountUserMap" type="account">
      <!--account的屬性,id代表其主鍵，result爲其他屬性-->
        <id column="aid" property="id"></id>
        <result property="uid" column="uid"></result>
        <result property="money" column="money"></result>
        <!--一對一,property是account的一個屬性，user，類型爲user類-->
        <association property="user" column="uid" javaType="user">
            <id column="id" property="id"></id>
            <result column="username" property="username"></result>
            <result column="address" property="address"></result>
            <result column="sex" property="sex"></result>
            <result column="birthday" property="birthday"></result>
        </association>
    </resultMap>

一對多

 <!--定義封裝account和user-->
    <resultMap id="RoleUserMap" type="role">
      <!--account的屬性,id代表其主鍵，result爲其他屬性-->
        <id column="rid" property="id"></id>
        <result property="roleName" column="role_name"></result>
        <result property="roleDesc" column="role_desc"></result>
        <!--這是使用collection集合，oftype爲封裝到javaBean類,也就是尖括號的泛型private List<Post>posts-->
        <collection property="users" ofType="user">
            <id column="id" property="id"></id>
            <result column="username" property="username"></result>
            <result column="address" property="address"></result>
            <result column="sex" property="sex"></result>
            <result column="birthday" property="birthday"></result>
        </collection>
    </resultMap>