One of the most important features of any information system is the database. It is very important to get the structure of the underlying data correct before you start the processing - a carefully designed database can remove the need for complicated validation, for example.
GCSE Computer Science specifications are unusual in that they expect you to know about certain aspects of database structure, e.g. records, and also SQL, but they don't included the word database.
Some of the database theory pages refer to the Merits database, created in Access. Click here to download a copy. For obvious reasons, much of the data has been removed.