You'd be surprised how little is recorded for most transactions. While it's possible to retain a full audit trail for data access, most systems don't. Answering

You'd be surprised how little is recorded for most transactions. While it's possible to retain a full audit trail for data access, most systems don't. Answering questions like "who looked at this database" is impossible in just about every system I've ever worked with. Some of the more sensitive financial or personal data systems might retain records of who changed a value, but even that is rare and in most cases easily faked or hidden.