Question

ibatis映射文件中的<selectKey>

<insert id="insert" parameterClass="projectObject">
<selectKey resultClass="java.lang.Long" keyProperty="projectId" >
SELECT HC_PROJECT_SEQ.NEXTVAL AS ID FROM DUAL
</selectKey>
INSERT INTO HC_PROJECT ( PROJECT_ID, PROJECT_NAME, PROJECT_DESCRIBE,FLAG)
VALUES ( #projectId#, #name#, #describle#,1)
</insert>

<selectKey>中间的的select语句什么意思，望详解？

Answer 1

SELECT HC_PROJECT_SEQ.NEXTVAL AS ID FROM DUAL
从sequences中取下一个值.
这是序列的操作,如果有疑问,请参阅ORACLE序列.

还有,我不知道楼主为什么这样写.
可以直接写成这样
<insert id="insert" parameterClass="projectObject">
INSERT INTO HC_PROJECT ( PROJECT_ID, PROJECT_NAME, PROJECT_DESCRIBE,FLAG)
VALUES ( HC_PROJECT_SEQ.NEXTVAL, #name#, #describle#,1)
</insert>