Mybatis insert 返回主键

在使用MyBatis作持久层时，insert语句默认是不返回记录的主键值，而是返回插入的记录条数；若是业务层须要获得记录的主键时，能够经过配置的方式来完成这个功能

针对Sequence主键而言，在执行insert sql前必须指定一个主键值给要插入的记录，如Oracle、DB2，能够采用以下配置方式：

<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>

针对自增主键的表，在插入时不须要主键，而是在插入过程自动获取一个自增的主键，好比MySQL，能够采用以下两种配置方式：

<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>

在插入操做完成以后，参数category的id属性就已经被赋值了

若是数据库表的主键不是自增的类型，那么就须要应用层生成主键的方式··········这个就很少说了，须要的朋友，能够留言交流··

---

下面是针对Oracle的写法,Oracle没有autoincrement，而是用触发器实现的 CURRVAL是在触发器中定义的.

<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>

<!-- 下面是针对MySQL的写法 -->

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

其余参考代码： 持久化某个实体对象（如保存一个对象）时，若是咱们不用selectKey，那么咱们不会马上获得实体对象的Id属性的，也就是数据表主键 Java代码

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

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

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

selectKey元素与其在父元素中的位置有关

<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在后 Xml代码

<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>

像上面这样书写，与selectKey的位置联系得太紧密了，iBatis的sqlMap配置文件的selectKey元素有个type属性，能够指定pre或者post表示前生成仍是后生成。 对于Oracle，表示为 Xml代码

<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等表示为： Xml代码

<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>

转自：

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

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

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