oracle中主键从增设置

oracle中主键自增设置

create table dectuser(

?????????? userid integer primary key,? /*主键，自动增加*/

?????????? name varchar2(20),

????????? ?sex varchar2(2)

?????????? );2、创建自动增长序列

????? drop sequence dectuser_tb_seq;

????? create sequence dectuser_tb_seq minvalue 1 maxvalue 99999999

?????????????? increment by 1

?????????????? start with 1;?? /*步长为1*/

?

<insert id="insert" parametertype="pre" keyProperty="id" >?
???????? SELECT STOCKIDSEQUENCE.NEXTVAL AS VALUE FROM DUAL?
??? </selectKey>?
???? insert into test (id,name) values (#irrd#,#myName#)?
</insert>

?

在进行数据的插入时，有的业务需要获得相应的生成的主键值，以下是ibatis的实现方式：
有些数据库是预生成(pre-generate)主键的，如Oracle和PostgreSQL；有些是后生成(post-generate)主键的，如MySQL和SQL Server。不管是哪种方式，都可以用iBATIS的<selectkey>节点来获取<insert>语句所产生的主键。

demo如下：

1. <!-- Oracle SEQUENCE Example using .NET 1.1 System.Data.OracleClient -->??<insert?id="insertProduct-ORACLE"?parameterClass="product">??
2. ????<selectKey?resultClass="int"?type="pre"?keyProperty="id"?>?????????? SELECT STOCKIDSEQUENCE.NEXTVAL AS VALUE FROM DUAL??
3. ????</selectKey>?????? insert into PRODUCT (PRD_ID,PRD_DESCRIPTION) values (#id#,#description#)??
4. </insert>????
5. <!-- Microsoft SQL Server IDENTITY Column Example -->??<insert?id="insertProduct-MS-SQL"?parameterClass="product">??
6. ???? insert into PRODUCT (PRD_DESCRIPTION)?????? values (#description#)??
7. ????<selectKey?resultClass="int"?type="post"?keyProperty="id"?>?????????? select @@IDENTITY as value??
8. ????</selectKey>??</insert>??
9. ??<!-- MySQL Example -->??
10. <insert?id="insertProduct-MYSQL"?parameterClass="product">?????? insert into PRODUCT (PRD_DESCRIPTION)??
11. ???? values (#description#)??????<selectKey?resultClass="int"?type="post"?keyProperty="id"?>??
12. ???????? select LAST_INSERT_ID() as value??????</selectKey>??
13. </insert>??