Delete records from SQL Server backup file

Question

It is an insane idea to delete records from backup since the notion of backup is to serve on disaster. But in our case, data deletion is a valid use-case.

Requirement: in brief, we are in need of a system which is capable of deleting a specific record from an active database instance and from all its backups.

We have a fully functional internal system which is capable of performing the mentioned requirement of deleting data from active database. But what we don't know is how to do the same agonist all these database backups.

Question:

• Is it possible to find a specific record from a backup?
• Is there any predefined schema or data allocation style within SQL Server backup file, which allow us to isolate a specific record?
• Can you share any thoughts or experience you have on such style of deletion?

Note: we take 2 full backup daily and store a week worth (14 in total) at any point in time.

Answer 1

I do understand the business concept of "deleted everywhere".

I do not know of any way to do this. I do not believe the format of the backup is even published. That doesn't mean that someone hasn't hacked it, but it certainly isn't a broadly known capability.

I think that, in order to do this, you will need to securely wipe all copies of backups and take new backups. You then lose the point in time recovery capability.

Solution : The way that I would address this business requirement is to recover each backup, delete the desired record(s), secure wipe the backup media (or destroy the old media and use new media), and then take a new backup of THAT recovered version. That will give you a point in time recovery of that data without the specific record(s).

Answer 2

You can't modify the contents of a .bak file. You shouldn't want to do that either. If you want to restore to a specific point in time you should use the Full recovery model and take differential and log backups instead of just full backups.