During my days as a DBA, I frequently received backup files from my manager, with instructions to restore the contents.  Here's what I usually do to get a handle on things:

·Run RESTORE LABELONLY on the file

The information provided tells me if the backup file is the only one in a backup set, or if the backup file is part of a backup set.  The FamilyCount and FamilySequenceNumber columns provide this information.  Recall that a backup may be spread across multiple files.  In such situations, you would need all the files in order to restore the database successfully.

·Run RESTORE HEADERONLY on the file

I use this to find out:

·the number of backups that are contained in the file.  A backup file may contain multiple backup sets.

·the backup type, whether if it's a full database backup, differential, log etc.

·the name of the database that was backed up.

·Run RESTORE FILELISTONLY on the file

I would only run this on a full database backup. Running this tells me the number of files that makes up the database, and the size of each file.  This allows me to know quickly if I have enough disk space to restore the database.

Can't we tell the size of the database from the backup file size?  No, if:

·the backup file contains multiple backup sets

·the database contains a lot of truncated data

·the database's tranaction log file contains mostly truncated data

In summary, there is a wealth of information you can retrieve from a backup file, using the RESTORE LABELONLY, RESTORE HEADERONLY and RESTORE FILELISTONLY commands.  See the Books Online documentation for these commands for more details.