一对一、一对多的关联查询？

一对一关联查询

xml

<mapper namespace="com.lcb.mapping.userMapper">  
  <select id="getClass" parameterType="int" resultMap="ClassesResultMap">  
    select * from class c,teacher t where c.teacher_id=t.t_id and c.c_id=#{id}  
  </select>  
  <resultMap type="com.lcb.user.Classes" id="ClassesResultMap">  
    <!-- 实体类的字段名和数据表的字段名映射 -->  
    <id property="id" column="c_id"/>  
    <result property="name" column="c_name"/>  
    <association property="teacher" javaType="com.lcb.user.Teacher">  
      <id property="id" column="t_id"/>  
      <result property="name" column="t_name"/>  
    </association>  
  </resultMap>  
</mapper>

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一对多关联查询

xml

<mapper namespace="com.lcb.mapping.userMapper">  
  <!--collection  一对多关联查询 -->  
  <select id="getClass2" parameterType="int" resultMap="ClassesResultMap2">  
    select * from class c,teacher t,student s where c.teacher_id=t.t_id and c.c_id=s.class_id and c.c_id=#{id}  
  </select>  
  <resultMap type="com.lcb.user.Classes" id="ClassesResultMap2">  
    <id property="id" column="c_id"/>  
    <result property="name" column="c_name"/>  
    <association property="teacher" javaType="com.lcb.user.Teacher">  
      <id property="id" column="t_id"/>  
      <result property="name" column="t_name"/>  
    </association>  
    <collection property="student" ofType="com.lcb.user.Student">  
      <id property="id" column="s_id"/>  
      <result property="name" column="s_name"/>  
    </collection>  
  </resultMap>  
</mapper>

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一对一、一对多的关联查询 ？ #

一对一、一对多的关联查询？