Renaming the Physical Filename for Datafiles in SQL Server 2008

using T SQL

ALTER DATABASE databaseName SET OFFLINE
GO


ALTER DATABASE databaseNAme MODIFY FILE (NAME =db, FILENAME = 'C:\Program
Files\Microsoft SQL Server\MSSQL.2\MSSQL\Data\db.mdf')
GO--if changing log file name

ALTER DATABASE  databaseNAme MODIFY FILE (NAME = db_log, FILENAME =
'C:\Program Files\Microsoft SQL Server\MSSQL.2\MSSQL\Data\db.ldf')
GO

ALTER DATABASE databaseName SET ONLINE
GO