MySQL backup pieces of the database from a server

Question

I'm writing the back-end for a web app in Spring and it uses a MySQL database on an AWS RDS instance to keep track of user data. Right now the SQL tables are separated by user groups (just a value in a column), so different groups have different access to data. Whenever a person using the app does a certain operation, we want to back up their part of the database, which can be viewed later, or replace their data in the current branch if they want.

The only way I can figure out how to do this is to create separate copies of every table for each backup and keep another table to keep track of what all the names of the tables are. This feels very inelegant and labor intensive.

So far all operations I do on the database are SQL queries from the server, and I would like to stay consistent with that.

Is there a nice way to do what I need?

Answer 1

Why would you want a separate table for each backup? You could have a single table that mirrored the main table but had a few additional fields to record some metadata about the change, for example the person making it, a timestamp, and the type of change either update or delete. Whenever a change is made, simply copy the old value over to this table and you will then have a complete history of the state of the record over time. You can still enforce the group-based access by keeping that column.

As for doing all this with queries, you will need some for viewing or restoring these archived changes, but the simplest way for maintaining the archived records is surely to create TRIGGERS on the main tables. If you add BEFORE UPDATE and BEFORE DELETE TRIGGERS these can copy the old version of each record over to the archive (and also add the metadata at the same time) each time a record is updated or deleted.