오라클 설치후 접속시 문제..

오라클 접속할때

sqlplus test/test 로 접속하면 잘되는데

sqlplus test/test@kdb 로접속하면.. 이런에러가 나버립니다.

ERROR:
ORA-12505: TNS:listener could not resolve SID given in connect descriptor

분명히 sid 가 kdb 맞거든요..

그리고 lsnrctl 에서 stat 해서보면 아래와 같이 나옵니다.

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=localhost)(PORT=1521))(CONNECT_DATA=(SID=KDB)))
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for Linux: Version 8.1.7.0.0 - Production
Start Date 15-OCT-2003 14:41:47
Uptime 0 days 0 hr. 2 min. 43 sec
Trace Level off
Security OFF
SNMP OFF
Listener Parameter File /Ext_home/ora/product/8.1.5/network/admin/listener.ora
Listener Log File /Ext_home/ora/product/8.1.5/network/log/listener.log
Services Summary...
KDB has 3 service handler(s)
KDB has 3 service handler(s)
The command completed successfully

========================listener.ora냉용=====================================

LISTENER =
(DESCRIPTION =
(ADDRESS_LIST=
(ADDRESS=(PROTOCOL=tcp)(HOST=localhost)(PORT=1521))
(ADDRESS=(PROTOCOL=ipc)(KEY=PNPKEY))
)
(CONNECT_DATA =
( SID = KDB )
)
)

============================================================

이유가 뭔지 궁금합니다.