Mybatis批量操作

批量插入
void batchInsertBackup(List<UserRights> list);
<insert id ="batchInsertBackup" parameterType="java.util.List" >
  insert into user_rights_backup
  (id,supplier_id,user_id,rights_id,rules_id,
  start_time,end_time,goods_no,has_num,type,
  status,ctime,mtime,biz_type,first_type,
  is_limit_time)
  values
  <foreach collection ="list" item="entityRecord" index= "index" separator =",">
    (
    #{entityRecord.id}, #{entityRecord.supplierId},#{entityRecord.userId},#{entityRecord.rightsId},#{entityRecord.rulesId},
    #{entityRecord.startTime}, #{entityRecord.endTime}, #{entityRecord.goodsNo},#{entityRecord.hasNum},#{entityRecord.type},
    #{entityRecord.status},#{entityRecord.ctime},#{entityRecord.mtime},#{entityRecord.bizType},#{entityRecord.firstType},
    #{entityRecord.isLimitTime}
    )
  </foreach >
</insert >

批量删除源数据
void batchDelete(List<UserRights> list);
<delete id="batchDelete" parameterType="java.util.List" >
  delete from user_rights where id in  (
  <foreach collection="list" item="entity" index= "index"  separator=",">
    #{entity.id}
  </foreach>
  )
</delete>

根据id，批量查询

List<UserRights> batchQuery(List<Long> idList);

<select id="batchQuery" resultMap="BaseResultMap" parameterType="java.util.List">
  select
  <include refid="base_column_list"/>
  from user_rights
  where id in
  <foreach collection="list" index="index" item="item" separator="," open="(" close=")">
    #{item,jdbcType=BIGINT}
  </foreach>
</select>



根据id,批量更新时间和状态
<update id="updateBatch" parameterType="java.util.List">
  update user_rights
  <trim prefix="set" suffixOverrides=",">
    <trim prefix="status = case" suffix="end,">
      <foreach collection="list" item="item" index="index">
        when id=#{item.id} then #{item.status}
      </foreach>
    </trim>
    <trim prefix=" start_time = case" suffix="end,">
      <foreach collection="list" item="item" index="index">
        when id=#{item.id} then #{item.startTime}
      </foreach>
    </trim>
  </trim>
  where id in
  <foreach collection="list" index="index" item="item" separator="," open="(" close=")">
    #{item.id,jdbcType=BIGINT}
  </foreach>
</update>

首先，mysql需要数据库连接配置&allowMultiQueries=true

jdbc:mysql://127.0.0.1:3306/mybank?useUnicode=true&characterEncoding=utf8&allowMultiQueries=true

oracle下支持执行多条语句，下面3个相同

<update id="batchUpdate" parameterType="java.util.List">
        <foreach collection="list" item="item" index="index" open="begin" close=";end;" separator=";" > 
            update T_EMP_1 
            <set>       
                age = #{item.age}+1,name=#{item.name}
            </set>
            where id = #{item.id}
        </foreach>
    </update>

<update id="batchUpdate" parameterType="java.util.List">
        <foreach collection="list" item="item" index="index" open="begin" close="end;" separator="" > 
            update T_EMP_1 
            <set>       
                age = #{item.age}+1,name=#{item.name}
            </set>
            where id = #{item.id};
        </foreach>
    </update>

<update id="batchUpdate" parameterType="java.util.List">
        begin
        <foreach collection="list" item="item" index="index" separator="" > 
            update T_EMP_1 
            <set>       
                age = #{item.age}+1,name=#{item.name}
            </set>
            where id = #{item.id};
        </foreach>
        end;
    </update>

foreach的主要用在构建in条件中，它可以在SQL语句中进行迭代一个集合。foreach元素的属性主要有 item，index，collection，open，separator，close。item表示集合中每一个元素进行迭代时的别名，index指定一个名字，用于表示在迭代过程中，每次迭代到的位置，open表示该语句以什么开始，separator表示在每次进行迭代之间以什么符号作为分隔符，close表示以什么结束，在使用foreach的时候最关键的也是最容易出错的就是collection属性，该属性是必须指定的，但是在不同情况下，该属性的值是不一样的，主要有一下3种情况：
1. 如果传入的是单参数且参数类型是一个List的时候，collection属性值为list
2. 如果传入的是单参数且参数类型是一个array数组的时候，collection的属性值为array
3. 如果传入的参数是多个的时候，我们就需要把它们封装成一个Map了，当然单参数也可以封装成map，实际上如果你在传入参数的时候，在breast里面也是会把它封装成一个Map的，map的key就是参数名，所以这个时候collection属性值就是传入的List或array对象在自己封装的map里面的key

批量删除

<delete id="batchDeleteStudent" parameterType="List">  
    DELETE FROM STUDENT WHERE id IN  
    <foreach collection="list" index="index" item="item" open="(" separator="," close=")">   
        #{item}   
    </foreach>  
</delete>

批量更新注意：oracle中形如 update *** set *** where ** in(....) 这种语句 in所在的集合有条数限制为1000条

<update id="batchUpdateStudent" parameterType="List">  
    UPDATE STUDENT SET name = "5566" WHERE id IN  
    <foreach collection="list" item="item" index="index" open="(" separator="," close=")" >  
        #{item}  
    </foreach>  
</update>

<update id="batchUpdateStudentWithMap" parameterType="Map" >  
    UPDATE STUDENT SET name = #{name} WHERE id IN   
    <foreach collection="idList" index="index" item="item" open="(" separator="," close=")">   
        #{item}   
    </foreach>  
</update>

批量插入 mysql和oracle不一样

mysql：
<insert id="batchInsertStudent" parameterType="java.util.List">  
    INSERT INTO STUDENT (id,name,sex,tel,address)  
    VALUES   
    <foreach collection="list" item="item" index="index" separator="," >  
        (#{item.id},#{item.name},#{item.sex},#{item.tel},#{item.address})  
    </foreach>  
</insert>

oracle：
<insert id="insertBatch4Oracle" parameterType="List">
        insert into aa(a,b)
        <foreach collection="list" item="item" index="index" separator="union all" >
         　　select  #{item.a},#{item.b} from dual
        </foreach>
 </insert>