Truncating a data file
The following example truncates the primary data file in the AdventureWorks database. The sys.database_files catalog view is queried to obtain the file_id of the data file.
http://msdn2.microsoft.com/en-us/library/ms189493.aspx
USE AdventureWorks; GO SELECT file_id, name FROM sys.database_files; GO DBCC SHRINKFILE (1, TRUNCATEONLY);