zoukankan      html  css  js  c++  java
  • oneselfone

    1.one2many-多表连接查询


    <mapper namespace="com.abc.dao.INewsLabelDao"> <!-- 多表连接查询 --> <resultMap type="NewsLabel" id="newslabelMap"> <id column="ptid" property="id"/> <result column="ptname" property="name"/> <collection property="children" ofType="NewsLabel"> <id column="cdid" property="id"/> <result column="cdname" property="name"/> </collection> </resultMap> <select id="selectNewsLabelById" resultMap="newslabelMap"> select pt.id ptid,pt.name ptname,cd.id cdid,cd.name cdname from newslabel pt,newslabel cd where pt.id=cd.pid and pt.id=#{xxx} </select> </mapper>

    2.one2many-多表单独查询

    <mapper namespace="com.abc.dao.INewsLabelDao">
        
        <!-- 多表单独查询 -->
    
        <select id="selectChildrenByParent" resultMap="newslabelMap">
            select id,name from newslabel where pid=#{jjj}
        </select>
    
        <resultMap type="NewsLabel" id="newslabelMap">
            <id column="id" property="id"/>
            <result column="name" property="name"/>
            <collection property="children" 
                        ofType="NewsLabel"
                        select="selectChildrenByParent"
                        column="id"/>
        </resultMap>
    
        <select id="selectNewsLabelById" resultMap="newslabelMap">
            select id,name from newslabel where id=#{xxx}
        </select>
    
    </mapper>

    3.one2many-多表单独查询2

    <mapper namespace="com.abc.dao.INewsLabelDao">
        
        <!-- 多表单独查询 -->
    
        <select id="selectChildrenByParent" resultMap="newslabelMap">
            select id,name from newslabel where pid=#{jjj}
        </select>
    
        <resultMap type="NewsLabel" id="newslabelMap">
            <id column="id" property="id"/>
            <result column="name" property="name"/>
            <collection property="children" 
                        ofType="NewsLabel"
                        select="selectChildrenByParent"
                        column="id"/>
        </resultMap>
    
    </mapper>

    4.many2one-多表单独查询

    <mapper namespace="com.abc.dao.INewsLabelDao">
        
        <!-- 多表单独查询 -->
    
        <resultMap type="NewsLabel" id="newslabelMap">
            <id column="id" property="id"/>
            <result column="name" property="name"/>
            <association property="parent" 
                         javaType="NewsLabel"
                         select="selectNewsLabelById"
                         column="pid"/>
        </resultMap>
        
        <select id="selectNewsLabelById" resultMap="newslabelMap">
            select id,name,pid from newslabel where id=#{jjj}
        </select>
    
    </mapper>
  • 相关阅读:
    python中的赋值与深浅拷贝
    PAT甲级:1089 Insert or Merge (25分)
    PAT甲级:1064 Complete Binary Search Tree (30分)
    navicat 15 破解教程
    SQL
    以初学者的角度理解:SQL实现关系除法
    线性回归与梯度下降(ML作业)
    海明码
    CRC校验原理
    Jupyter notebook总是卡在int[*]怎么解决?
  • 原文地址:https://www.cnblogs.com/csslcww/p/9912371.html
Copyright © 2011-2022 走看看