What does a DVD shop use database for?

They could use them for lots of things, like keeping lists of their stock, lists of their customers, lists of their suppliers etc. These could then be used to generate reports or allow them to search for a DVD when a customer comes in, so that they can tell if they have it, where in the shop to find it, its price etc. They could use the databases for all sorts of calculations and analysis, like finding out what DVDs are most popular.

DVD stores will usually use a database system which is running as the main application of the EPOS system (Electronic Point Of Sale) more often called the checkout or till. This system is managed by a back office server where sales data , inventry and financial data is stored for use in the running of the business. In additon stores which not only sell but rent DVDs use a seconary application (a CRM) to log customers (renters) details and user history. This also in the main access the main data files.