5. Multi-user booking system

Some travel agencies have branches all over the country. And yet they will all by trying to book the same package holidays and travel arrangement for their customers.

There must not be over-booking or double booking.

This is only possible because there is a central database held in the main headquarters and every branch has a set of terminals connecting remotely to it. This is called a multi-user system

As soon as a branch makes a booking, the central record is updated. For example, consider there are 300 slots available for a particular package holiday. The agencies have been busy and the holiday package is selling fast. The database record at one point in time may look like this

Every time a booking is made, the current slots available is by 1 until no more are left. There will of course be records in other tables within the database storing the details of every customer.