If you need to create a new database for each user, I'd suggest radically rethinking your approach to the problem.
Very few problems require going that far.
For a booking system, for instance, I would imagine you would need one database with the following tables:
- A user table with the user information for each user
- A hotel table (if it's hotel booking, substitute what you need) with information on the hotels-
- A booking table that links each booking to a user, a hotel and a time.
Edit:
An example of a problem for which it would be suited would be a meta-booking system; as in a system where you could set up a booking system for your own site or whatever.
If that is what you need, ignore this.