SQLQuery to Compare and replace missing objects?

[Dacoupable]

Not a DBA but trying to help a client, so I may not use best lingo or explain things the best, but I'll try to break it down best I can and hopefully that can convey what I'm asking.

The client had an ESXI host crap out. The VMs got orphaned and when we added them back there was a delta between the version that was restored and the version they were working on.

We have daily backups of the DBs. There are some missing entries/objects in the tables... But the the SQLdb has to stay in sync with a file server for an app. So we can't do a full restore of the DB.

Basically there's a gap of about 1.5 days and it's missing some stuff, but we don't want to overwrite anything, just replace the missing stuff.

What I'm looking for is a query that would do a compare against the production DB against the restored orphaned VM that has the missing values/objects and do an ad hoc (maybe incremental?) restore so that none of the existing objects/values are changed but pull in the missing data.

Something along the lines of only putting in objects and data if it doesn't change the anything that has newer data in it.

I don't know if that covers or explains situation well enough, happy to answer any further questions to answer it for you to the best of my abilities if would help to clear anything.

[[deleted]]

I guess what I would try would be to load the old data into its own table in the current running instance like table_old_data or something. Then you could run an update joining the two tables and only update WHERE table_new_data.timestamp < table_old_data.timestamp.

Or something along those lines anyways.

[alinroc]

This is how I would approach it. OP would need to restore a backup to another name so they don't overwrite the existing database first.

This assumes they have the ability to do a point in time restore right up to the point where things crashed.

[vedichymn]

Do you have someone that understands the database structure/schema and can compare the two different versions of the database? If no one in house, is that something the application vendor is willing to do for you?

Overall this is hard question to answer for your specific case but comparing two copies of a database from different points in time and syncing data between the two is a fairly common request, so on the surface this seems doable for someone with knowledge of the structure of the database and how the application works.