如何在分布式环境中预取Oracle序列ID-s

为什么不一直将序列增加100？每个"nextval"为您提供100个序列号

SQL> create sequence so_test start with 100 increment by 100 nocache;

Sequence created.

SQL> select so_test.nextval - 99 as first_seq, so_test.currval as last_seq from dual;

 FIRST_SEQ   LAST_SEQ
---------- ----------
         1        100

SQL> /

 FIRST_SEQ   LAST_SEQ
---------- ----------
       101        200

SQL> /

 FIRST_SEQ   LAST_SEQ
---------- ----------
       201        300

SQL> 

关于你的例子的注释..注意DDL ..它将产生一个隐式提交

DDL生成的提交示例

SQL> select * from xx;

no rows selected

SQL> insert into xx values ('x');

1 row created.

SQL> alter sequence so_test increment by 100;

Sequence altered.

SQL> rollback;

Rollback complete.

SQL> select * from xx;

Y
-----
x

SQL>