Why the DBID is same?

Question

I have Installed 2 databases on a same host(WinXP-32bits).
They are:
db_name:orcl6, orcl7
services: orcl6, orcl7
sid: orcl6, orcl7
But when I use follow command,I find the DBIDs are same.
SELECT DBID, NAME FROM V$DATABASE; (display follows):
DBID NAME
767363627 ORCL6
767363627 ORCL7
Why the DBIDs are same for 2 differerent database on a same system.
Message was edited by:
frank.qian
Message was edited by:
frank.qian

Answer 1

SQL*Plus: Release 10.2.0.1.0 - Production on 星期三 10月 31 22:27:10 2007
Copyright (c) 1982, 2005, Oracle. All rights reserved.
请输入用户名: sys as sysdba
输入口令:
连接到:
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning, OLAP and Data Mining options
SQL> select dbid,name from v$database;
DBID NAME
767363627 ORCL7
SQL> connect sys@orcl6 as sysdba
输入口令:
已连接。
SQL> select dbid,name from v$database;
DBID NAME
817045078 ORCL6
SQL>