Mybatis insert 返回主鍵

在使用MyBatis作持久層時，insert語句默認是不返回記錄的主鍵值，而是返回插入的記錄條數；若是業務層須要獲得記錄的主鍵時，能夠經過配置的方式來完成這個功能

針對Sequence主鍵而言，在執行insert sql前必須指定一個主鍵值給要插入的記錄，如Oracle、DB2，能夠採用以下配置方式：

<insert id="add" parameterType="vo.Category">

<selectKey resultType="Java.lang.Short" order="BEFORE" keyProperty="id">

SELECT SEQ_TEST.NEXTVAL FROM DUAL

</selectKey>

insert into category (name_zh, parent_id,

show_order, delete_status, description

)

values (#{nameZh,jdbcType=VARCHAR},

#{parentId,jdbcType=SMALLINT},

#{showOrder,jdbcType=SMALLINT},

#{deleteStatus,jdbcType=BIT},

#{description,jdbcType=VARCHAR}

)

</insert>

針對自增主鍵的表，在插入時不須要主鍵，而是在插入過程自動獲取一個自增的主鍵，好比MySQL，能夠採用以下兩種配置方式：

<insert id="add" parameterType="vo.Category" useGeneratedKeys="true" keyProperty="id">

insert into category (name_zh, parent_id,

show_order, delete_status, description

)

values (#{nameZh,jdbcType=VARCHAR},

#{parentId,jdbcType=SMALLINT},

#{showOrder,jdbcType=SMALLINT},

#{deleteStatus,jdbcType=BIT},

#{description,jdbcType=VARCHAR}

)

</insert>

或

<insert id="add" parameterType="vo.Category">

<selectKey resultType="java.lang.Short" order="AFTER" keyProperty="id">

SELECT LAST_INSERT_ID() AS id

</selectKey>

insert into category (name_zh, parent_id,

show_order, delete_status, description

)

values (#{nameZh,jdbcType=VARCHAR},

#{parentId,jdbcType=SMALLINT},

#{showOrder,jdbcType=SMALLINT},

#{deleteStatus,jdbcType=BIT},

#{description,jdbcType=VARCHAR}

)

</insert>

在插入操做完成以後，參數category的id屬性就已經被賦值了

若是數據庫表的主鍵不是自增的類型，那麼就須要應用層生成主鍵的方式··········這個就很少說了，須要的朋友，能夠留言交流··

---

下面是針對Oracle的寫法,Oracle沒有autoincrement，而是用觸發器實現的 CURRVAL是在觸發器中定義的.

<insert id="insert" parameterClass="ProFeeKindObject">
      <![CDATA[
         INSERT INTO t_pro_feeKind (KINDID,kindName,kindType,enable)
         VALUES (seq_t_pro_feekind_id.nextval,#kindName#,#kindType#,#enable#)
        ]]>
        <selectKey resultClass="java.lang.Integer" keyProperty="kindId" >
        SELECT seq_t_pro_feekind_id.CURRVAL AS kindId FROM DUAL
        </selectKey>    
</insert>

<!-- 下面是針對MySQL的寫法 -->

<!--
   <selectKey resultClass="int" keyProperty="id" >
   SELECT @@IDENTITY AS id
   </selectKey>
-->

其餘參考代碼： 持久化某個實體對象（如保存一個對象）時，若是咱們不用selectKey，那麼咱們不會馬上獲得實體對象的Id屬性的，也就是數據表主鍵 Java代碼

Permission permission = new Permission();
permission.set...

permmisonDao.createPermission(permission);
assertNull(permission);
Permission permission = new Permission();
permission.set...

permmisonDao.createPermission(permission);
assertNull(permission);

selectKey元素與其在父元素中的位置有關

<insert id="addPermission" parameterClass="Permission">   
     <selectKey resultClass="int" keyProperty="permissionId">   
         SELECT SEQ_P_PERMISSION.NEXTVAL FROM DUAL    
     </selectKey>   
     INSERT INTO P_PERMISSION (
         PERMISSIONID, PERMISSIONINFO, PERMISSIONNAME, PERMISSIONENNAME, URL
     ) VALUES (
         #permissionId#, #permissionInfo#, #permissionName#, #permissionEnName#, #url#
     )    
</insert>

<insert id="addPermission" parameterClass="Permission">
<selectKey resultClass="int" keyProperty="permissionId">
SELECT SEQ_P_PERMISSION.NEXTVAL FROM DUAL  
</selectKey>
INSERT INTO P_PERMISSION (
PERMISSIONID, PERMISSIONINFO, PERMISSIONNAME, PERMISSIONENNAME, URL
) VALUES (
#permissionId#, #permissionInfo#, #permissionName#, #permissionEnName#, #url#
)  
</insert>

Mysql、SQLServer在後 Xml代碼

<insert id="addPermission" parameterClass="Permission">     
INSERT INTO P_PERMISSION (
     PERMISSIONID, PERMISSIONINFO, PERMISSIONNAME, PERMISSIONENNAME, URL
) VALUES (
     #permissionId#, #permissionInfo#, #permissionName#, #permiss
ionEnName#, #url#
)
<selectKey resultClass="int" keyProperty="permissionId">   
     SELECT LAST_INSERT_ID()    
</selectKey>
</insert>

<insert id="addPermission" parameterClass="Permission">   
INSERT INTO P_PERMISSION (
PERMISSIONID, PERMISSIONINFO, PERMISSIONNAME, PERMISSIONENNAME, URL
) VALUES (
#permissionId#, #permissionInfo#, #permissionName#, #permissionEnName#, #url#
)
<selectKey resultClass="int" keyProperty="permissionId">
SELECT LAST_INSERT_ID()  
</selectKey>
</insert>

像上面這樣書寫，與selectKey的位置聯繫得太緊密了，iBatis的sqlMap配置文件的selectKey元素有個type屬性，能夠指定pre或者post表示前生成仍是後生成。 對於Oracle，表示爲 Xml代碼

<insert id="addPermission" parameterClass="Permission">   
    <selectKey resultClass="int" keyProperty="permissionId" type="pre">   
        SELECT SEQ_P_PERMISSION.NEXTVAL FROM DUAL    
    </selectKey>   
    INSERT INTO P_PERMISSION (
        PERMISSIONID, PERMISSIONINFO, PERMISSIONNAME, PERMISSIONENNAME, URL
    ) VALUES (
        #permissionId#, #permissionInfo#, #permissionName#, #permissionEnName#, #url#
    )    
</insert>

<insert id="addPermission" parameterClass="Permission">
<selectKey resultClass="int" keyProperty="permissionId" type="pre">
SELECT SEQ_P_PERMISSION.NEXTVAL FROM DUAL  
</selectKey>
INSERT INTO P_PERMISSION (
PERMISSIONID, PERMISSIONINFO, PERMISSIONNAME, PERMISSIONENNAME, URL
) VALUES (
#permissionId#, #permissionInfo#, #permissionName#, #permissionEnName#, #url#
)  
</insert>

Mysql、SQLServer等表示爲： Xml代碼

<insert id="addPermission" parameterClass="Permission">   
     <selectKey resultClass="int" keyProperty="permissionId" type="post">   
         SELECT LAST_INSERT_ID()
     </selectKey>   
     INSERT INTO P_PERMISSION (
         PERMISSIONID, PERMISSIONINFO, PERMISSIONNAME, PERMISSIONENNAME, URL
     ) VALUES (
         #permissionId#, #permissionInfo#, #permissionName#, #permissionEnName#, #url#
     )    
</insert>

轉自：

http://289972458.iteye.com/blog/1001851

            http://hi.baidu.com/zim_it/blog/item/8a2bd11205f5b56ecb80c4b7.html

            http://blog.csdn.net/jbgtwang/article/details/7307687