When I recently applied for a job, I gave my former boss' name on an employment form as supervisor. I was under the impression they would check only my personal references and limit discussions with my former company to dates, salary, job role.
However I am under the impression my former boss gave me a bad reference. I plan not to list him next time, but I wonder if it stays in a database for these 3rd party reference checkers. If my next target employer uses this same 3rd party, I am worried they may say what happen with the last potential employer. Can I assume they start fresh on each background check?
I know there is always a risk they can locate my old boss, but I am more concerned about the database piece.
There are weird assumptions in this letter.
First, good reference-checkers will not limit themselves to just the formal list of references you provide. They will call former managers, listed or not -- and sometimes especially those not listed, since they know the omission may have been intentional and thus notable. (After all, the list you hand over is of course the people likely to present you in the best light, and they want to see you in brighter lighting.) And they won't confine their questions to dates of employment; they'll ask what you were like as an employee.
The only thing typically considered off-limits in reference-checking is your current employer, so assume everything else is all fair game.
As for some sort of universal database for reference-checkers, I know of none. Good reference checkers want to ask their own questions and hear the answers first-hand so they can judge tone, inflections, and so forth. That said, I suppose that if a company uses a third-party reference-checking firm, and then you later apply to another company that uses that same firm, you might be already in their database. I don't use third-party reference checkers, so it's outside my knowledge range. But it's probably irrelevant for the reason above.
If you have a potentially bad reference in your past, here's a previous post on how to handle it. Good luck.