How to reduce database size/ getting back unused space to OS

From: Sheetu (Sheetu_at_discussions.microsoft.com)
Date: 07/02/04 

Date: Fri, 2 Jul 2004 07:20:01 -0700

Hi All,
I have got Central site SMS database whose size is 27 GB. But when I browse it through SQl Enterprise manager, I could see there that only 12GB space is used and rest of 15 GB space is free. I have already tried shrinking the database but could not succeded. The SQL command which I have used is:
DBCC shrinkdatabse (SMS_DB, Truncateonly)
 
Could anybody suggest how to get space released to the operating system from the databse which is unused.

Thanks in advance

:) Sheetu