After Piecemeal Primary FileGroup Restoration, Database Property Window Shows other FileGroups also

Question

Hi,
I have a SQL Server 2008 database with 90 Gigs of Capacity.
The database consists of a huge table with 80 Gigs of Capacity and these entire 80 Gigs of data is Static in nature.
We need the to restore the backup of this database frequently in to the Development environment, so we moved this static data into a Secondary File Group.
Now, the database Consists of 2 Filegroups : Primary & Secondary_fg.
The entire Static table is moved to the Secondary FileGroup.
We have taken the backup of Primary FileGroup using the following Backup Command :
Backup Database MYDB FILEGROUP = 'PRIMARY' to disk = 'E:\SQLBackup\MYDB_Primary_FG_Only.bak'
WITH NOFORMAT, NOINIT, NAME = N'MYDB - Full Filegroup backup', SKIP, NOREWIND, NOUNLOAD
The backup went file with the expected capacity of 10 Gigs.
I have restored this backup in to a New Database : MYDB_PRIMARY_ONLY using the following command
RESTORE DATABASE [MYDB_PRIMARY_ONLY] FILE = 'MYDB_DATA', FILEGROUP = 'PRIMARY'
FROM DISK = 'E:\SQLBackup\MYDB_Primary_FG_Only.bak',
WITH FILE=1,
MOVE 'MYDB_DATA' TO 'E:\SQLDATA\MYDB_PRIMARY_ONLY_DATA.mdf',
MOVE 'MYDB_LOG' TO 'E:\SQLDATA\MYDB_PRIMARY_ONLY_LOG.ldf', NOUNLOAD, PARTIAL
GO
The Restoration also went fine and the size of the Newly Restored Database : "MYDB_PRIMARY_ONLY" is with 10 Gigs in Capacity.
But, the gotcha here is whilst checking the Database Properties of this Newly restored database, on the FILES & FILEGROUPS tab, the files & filegroups related to the SECONDARY FILEGROUP is also showing.
MY ACTUAL QUESTION :
On the PRIMARY FILEGROUP ONLY RESTORATION HOW THIS SECONDARY FILEGROUP IS COMING INTO PICTURE ?
MOREOVER, WHEN I TRIED TO REMOVE THE SECONDARY FILEGROUP AND IT'S RESPECTIVE DATA FILE IT THROUGH THE FOLLOWING ERROR :
COMMAND USED TO REMOVED THE FILE & FILEGROUP :
USE [MYDB_PRIMARY_ONLY]
GO
ALTER DATABASE [MYDB_PRIMARY_ONLY]  REMOVE FILE [SECONDARY_DATA_FILE.ndf]
GO
ALTER DATABASE [MYDB_PRIMARY_ONLY] REMOVE FILEGROUP [SECONDARY_FG]
GO
Error :
Msg 5056, Level 16, State 2, Line 1
Cannot add, remove, or modify a file in filegroup 'SECONDARY_FG' because the filegroup is not online.
Can anyone explain why such this error message ? Thanks in advance for any guidance in this regard.

Answer 1

On the PRIMARY FILEGROUP ONLY RESTORATION HOW THIS SECONDARY FILEGROUP IS COMING INTO PICTURE ?
When you restore only the primary filegroup, all database meta data is restored, including references to the filegroups and files not yet restored.  Filegroups/files not restored will be recovery pending state and data on those filegroups will be inaccessible. 
Removing the filegroup will change the status to defunct but the meta data will remain.  You'll need to copy the restored objects and data to a new clean database if you want to tidy up.
Dan Guzman, SQL Server MVP, http://www.dbdelta.com