插入数据时返回主键

<!-- mysql
<select id="insertUser"  parameterType="com.cjq.vo.User">
<selectKey keyProperty="id" order="AFTER" resultType="int">
select LAST_INSERT_ID()
</selectKey>
insert into user(username,age,sex) values(#{username},#{age},#{sex})
</insert>
-->

<!-- oracle
在执行insert之前执行select 序列.nextval() from dual取出序列最大值，将值设置到user对象 的id属性
-->
<!-- <insert id="insertUser" parameterType="com.cjq.vo.User">
<selectKey keyProperty="id" order="BEFORE" resultType="int">
select 序列.nextval() from dual
</selectKey>

INSERT INTO USER(id,username,age,sex) VALUES(#{id},#{username},#{age},#{sex})
</insert> -->