apache derby 的以下 sql 语句可以正常工作:
connect 'jdbc:derby://uri';
create schema TEST02;
set schema TEST02 ;
create table T
(
id INT not null primary key GENERATED BY DEFAULT AS IDENTITY (START WITH 1, INCREMENT BY 1),
name varchar(50) not null unique
);
insert into T(name) values ('NAME02');
insert into T(name) values ('NAME03');
select * from T;
drop table T ;
drop schema TEST02 RESTRICT;
disconnect;
输出:
ij> insert into T(name) values ('NAME02');
1 row inserted/updated/deleted
ij> insert into T(name) values ('NAME03');
1 row inserted/updated/deleted
ij> select * from T;
ID |NAME
--------------------------------------------------------------
1 |NAME02
2 |NAME03
但是当我“知道”一些记录的 id 并在我的 INSERT 语句中设置 id 时:
## here I set the id column
ij> insert into T(id,name) values (1,'NAME01');
1 row inserted/updated/deleted
ij> insert into T(name) values ('NAME02');
ERROR 23505: The statement was aborted because it would have caused a duplicate key value in a unique or primary key constraint or unique index identified by 'SQL130515100041380' defined on 'T'.
ij> insert into T(name) values ('NAME03');
1 row inserted/updated/deleted
ij> select * from T;
ID |NAME
--------------------------------------------------------------
1 |NAME01
2 |NAME03
2 rows selected
我该如何解决这个问题,我怎样才能有一个 auto_increment 列,有时我可以设置主键?