Not always. In fact, I'd strengthen that and say that this is not a problem in general/in most cases with thousands of concurrent users. See my other comment one level up.
If the app is designed correctly, then the thousand employees would write to their own temporary databases, and a background job would pull their changes into the main database sequentially.
If the app is not specifically designed to do this, then SQLite would not be an option.
Serious question, is this just a "how do I get SQLite to work in this scenario?" thing, or is there actually some other benefit to having this sort of data architecture?
This can actually relate to SMTP servers using mbox or maildir formats. Maildir is more resistant to corruption, and doesn't rely (as much) on file locks.
