mybatis 3 selectkey inside foreach

Question

MyBatis 3 - Spring

我想插入项目列表，并且每个项目 ID 都必须从 "TVA_UPSELLADMIN_CHANNEL_SEQ.nextVal" 生成，但我收到了 .xml 验证错误，您不能子级 "selectKey"里面"foreach".

<insert id="insertServiceMappings" parameterType="java.util.List">

INSERT  
<foreach collection="list" item="channel" index="index" >

<selectKey keyProperty="id" resultType="long" order="BEFORE">
            SELECT TVA_UPSELLADMIN_CHANNEL_SEQ.nextVal from dual
        </selectKey>

into tva_upselladmin_channel (id,source_id, service_id, name) values (#{id}, #{channel.sourceId}, #{channel.serviceId}, #{channel.name})
</foreach>
</insert>

Answer 1

MyBatis 当前版本（或任何与此相关的版本）不允许在 <forEach> 标签内使用 <selectKey>。它是否仅用于遍历列表。

<foreach> 标签的 MyBatis dtd 验证部分如下：

<!ELEMENT foreach (#PCDATA | include | trim | where | set | foreach | choose | if | bind)*>
<!ATTLIST foreach
collection CDATA #REQUIRED
item CDATA #IMPLIED
index CDATA #IMPLIED
open CDATA #IMPLIED
close CDATA #IMPLIED
separator CDATA #IMPLIED
>

因此，为了解决您的问题，您必须遍历您的列表，在您的 XML 上设置所有带有额外 select 定义的 ID。就像：

<select id="nextvalKey" resultType="java.lang.Integer">
     SELECT TVA_UPSELLADMIN_CHANNEL_SEQ.nextVal from dual
</select>

您的插入部分如下：

<insert id="insertServiceMappings" parameterType="java.util.List">
    <foreach collection="list" item="channel" index="index" >
        INSERT INTO tva_upselladmin_channel (id,source_id, service_id, name)
              VALUES ( #{id}, #{channel.sourceId}, #{channel.serviceId}, #{channel.name});
    </foreach>
</insert>

不要忘记插入命令后的;，因为ORACLE不支持多值插入，例如insert ... values (1,'bla'), (2, 'ble'), (3, 'bli');)

所以第二部分是在你的实现中有一个方法来为列表中的项目设置每个 id。它会是这样的：

  public void someMethodInsertList(List<SomeObject> list){
       //normally I do an implementation that allows me to use
       //sqlSessionTemplate from mybatis through an extended class 
       for ( SomeObject obj : list ){
           obj.setId( getSqlSessionTemplate.selectOne( 'nextvalKey' ) );
       }
       getSqlSessionTemplate.insert( 'insertServiceMappings', list );
  }

希望对您有所帮助

Answer 2

我找到了另一个解决方案，如下所示，它对我有用！

 <insert id="insertServiceMappings" parameterType="java.util.List" useGeneratedKeys="true">
         <selectKey keyProperty="id" resultType="java.lang.Long" order="BEFORE">
                SELECT TVA_UPSELLADMIN_CHANNEL_SEQ.nextVal as id FROM DUAL
         </selectKey>    
         INSERT INTO
         tva_upselladmin_channel (id,source_id, service_id, name)
         SELECT TVA_UPSELLADMIN_CHANNEL_SEQ.nextVal, A.* from (
         <foreach collection="list" item="channel" index="index" separator="union all">
         SELECT 
           #{channel.sourceId} as source_id,
           #{channel.serviceId} as service_id,
           #{channel.name}) as name
         FROM DUAL
         </foreach> ) A
    </insert>

mybatis 3 selectkey inside foreach

mybatis 3 selectkey inside foreach

java

spring

mybatis