Mybatis动态更新数据

冷不防 2022-07-11 23:26 487阅读 0赞

## Mybatis动态更新数据 ##

原理同上一篇的 [Mybatis动态插入数据（使用trim标签）][Mybatis_trim] ，控制同一张表，但传入的参数不固定，操作表的字段不固定，就要用到mybatis动态更新，普通的`<if test=" ">`的方法会出现多余的字符。

方法一：使用set标签

<update id="updateMessage"  parameterType="com.sf.ccsp.member.client.request.MessageReq" >
         update cx_customer_message
         <set>
            <if test='messageClassify != null and messageClassify != "" '>
              MESSAGEE_CLASSIFY = #{messageClassify, jdbcType=VARCHAR},
            </if>
            <if test='messageCode != null and messageCode != "" '>
              MESSAGE_CODE = #{messageCode, jdbcType=VARCHAR},
            </if>
            <if test='messageContent != null and messageContent != "" '>
              MESSAGE_CONTENT = #{messageContent, jdbcType=VARCHAR},
            </if>
         </set>
         where ID = #{id, jdbcType=VARCHAR}
         and MEMBERID = #{memberId, jdbcType=VARCHAR} 
    </update>

方法二：使用trim标签

<update id="updateMessage"  parameterType="com.sf.ccsp.member.client.request.MessageReq" >
         update cx_customer_message
         <trim prefix="set" suffixOverrides=",">  
            <if test='messageClassify != null and messageClassify != "" '>
              MESSAGEE_CLASSIFY = #{messageClassify, jdbcType=VARCHAR},
            </if>
            <if test='messageCode != null and messageCode != "" '>
              MESSAGE_CODE = #{messageCode, jdbcType=VARCHAR},
            </if>
            <if test='messageContent != null and messageContent != "" '>
              MESSAGE_CONTENT = #{messageContent, jdbcType=VARCHAR},
            </if>    
         </trim>  
         where ID = #{id, jdbcType=VARCHAR}
         and MEMBERID = #{memberId, jdbcType=VARCHAR} 
    </update>

[Mybatis_trim]: http://blog.csdn.net/u012780336/article/details/54880265