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>
-->
其他参考代码：
持久化某个实体对象（如保存一个对象）时，如果我们不用selectKey，那么我们不会立刻得到实体对象的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，可以指定pre或者post表示前生成还是后生成。
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>