Alter DATABASE olddb
MODIFY FILE(NAME=olddb_data,NEWNAME=newdb_data)
Alter DATABASE olddb
MODIFY FILE(NAME=olddb_log,NEWNAME=newdb_log)
EXEC sp_dboption "olddb", "Single User", "TRUE"
exec sp_renamedb "olddb","newdb"
EXEC sp_dboption "newdb", "Single User", "FALSE"