During the initial prototype evaluation of the webshop, Eventbase discovered that some clients would add tickets to their online basket and then browse through the available add-ons for the event adding some add-ons to the basket. However, when they went to pay for the content of their basket they would be told that the event tickets could not be purchased as they had already been sold and the entire basket sale is rejected. This occurred most often for popular events when only a few tickets remained available and when the user had spent some considerable time browsing through the add-ons. When the data was examined, the tickets that had been in the users basket were showing as sold to another user.

Briefly explain why the Eventbase webshop application described above could use a transaction management system capable of realising the ACID properties for transactions to prevent the above problem arising. You should include a description of how the above problem might have occurred, and which of the four ACID properties this particular example demonstrates.

Why are the other three ACID properties important to Eventbase when developing the webshop? Give examples of the potential problems they could prevent.

You do not need to write any SQL code for your answer to this question, but you may refer to SQL features in your answer.