Mybatis批量更新数据库与批量插入数据库（以oracle为例）

一、批量更新

1、普通写法（一条记录update一次，性能比较差，容易造成阻塞。不建议使用）

<update id="updateBatch"  parameterType="java.util.List">  
    <foreach collection="list" item="item" index="index" open="" close="" separator=";">
        update course
        <set>
            name=${item.name}
        </set>
        where id = ${item.id}
    </foreach>      
</update>

2、使用case when语法来实现这个功能（推荐使用）

UPDATE course
    SET name = CASE id 
        WHEN 1 THEN 'name1'
        WHEN 2 THEN 'name2'
        WHEN 3 THEN 'name3'
    END, 
    title = CASE id 
        WHEN 1 THEN 'New Title 1'
        WHEN 2 THEN 'New Title 2'
        WHEN 3 THEN 'New Title 3'
    END
WHERE id IN (1,2,3)

这条sql的意思是，如果id为1，则name的值为name1，title的值为New Title1；依此类推。

mybatis的XML文件配置

<update id="updateBatch" parameterType="list">
            update course
            <trim prefix="set" suffixOverrides=",">
             <trim prefix="peopleId =case" suffix="end,">
                 <foreach collection="list" item="i" index="index">
                         <if test="i.peopleId!=null">
                          when id=#{i.id} then #{i.peopleId}
                         </if>
                 </foreach>
              </trim>
              <trim prefix=" roadgridid =case" suffix="end,">
                 <foreach collection="list" item="i" index="index">
                         <if test="i.roadgridid!=null">
                          when id=#{i.id} then #{i.roadgridid}
                         </if>
                 </foreach>
              </trim>
              
              <trim prefix="type =case" suffix="end," >
                 <foreach collection="list" item="i" index="index">
                         <if test="i.type!=null">
                          when id=#{i.id} then #{i.type}
                         </if>
                 </foreach>
              </trim>
       <trim prefix="unitsid =case" suffix="end," >
                  <foreach collection="list" item="i" index="index">
                          <if test="i.unitsid!=null">
                           when id=#{i.id} then #{i.unitsid}
                          </if>
                  </foreach>
           </trim>
             </trim>
            where
            <foreach collection="list" separator="or" item="i" index="index" >
              id=#{i.id}
          </foreach>
</update>

 二、批量插入mybatis的XML文件配置

<insert id="insertMutil" parameterType="java.util.List">
        insert all
        <foreach collection="list" item="item" index="index"
            separator=" ">
            into SPSZMBB (ID, MBMC, HDCS, ZDHDS, SHID, FJS, SZSJ,SZRY)
            values
            (#{item.id},#{item.mbmc},#{item.hdcs},#{item.zdhds},#{item.shid},#{item.fjs},#{item.szsj},#{item.szry})
        </foreach>
        select 1 from dual
    </insert>