You are looking at a very old, but free version of the course. If you are interesed the most recent version, check it out on the Perl Maven site.
This can be considered as part of any application as there is some kind of a database used by every application. In the simple case the 'database' might be a flat file but it can also be some csv file or xml file or an RDBMS that you can access using SQL. In this case you would like to test what are the consequences on the database of certain operations of the application ?