That Blue Square Thing

Applied ICT A Level Unit 3 - Database Design

Note: this page applies to the AQA Applied ICT A level specification. This exam was withdrawn in 2012, with final exams in 2013. The content will be retained as an archive and because it has some stuff that might be quite useful for someone or other

Circuit board imageDatabases are everywhere.

Websites, stores, businesses, schools - databases are one of the key applications in modern computing. You could argue that they form the absolute basis of much of what we consider as ICT. Just imagine: how would your cell phone work without databases?

Unit 3 deals with basic relational databases. We don't want to get too complex here; we're only looking at fairly basic applications.

The key thing to understand about relational databases is that we organise information in different tables. So, for Bagshaw's Vets all the data about animals (their name, their date of birth, their species and so on) would go in one table and all the information about owners in another. The tables of data (or relation schemes if you want a techier term) contain fields of specific types. The tables are then connected together by links made between them.

This allows the database structure to be more efficient and for tables to store information about individual objects (techy: entities). The trick is that you really need to design your database effectively.

If you're looking for it, here's the Database Query Designer Tool.

A Database for Unit 3:

You need to build a database for a client.

This means that you need to have a specific user (or group of users) in a specific organisation.

It is strongly suggested that you identify a real client. The client’s needs are important in this unit and without a real client it is more difficult to access higher marks. Want to know how I know that? The markers told me, look:

"Where candidates had engaged with a real client the portfolio of work often had a narrower focus with the candidate having a clearer idea of how what they produced was meeting the needs stated. This tended to make it easier for those candidates to access the higher marks."

AQA examiners report, June 2007

Ideally your client would be a small organisation with limited ICT capabilities. Otherwise, wouldn't they already be using a bespoke ICT solution to do the job? There should be a fairly small number of potential users for the system you produce.

Clients and Customers:
You have a client. This is the person in an organisation who you are building the database for. Whenever I use the term client on these pages that's who I'm talking about.
Your client has customers - people who their organisation provides goods and services to (or sells stuff to). Whenever I use the term customer on these pages that's who I'm talking about.

What the client needs:

The client should have a clear need for a database system. The key question to consider first of all is "what does the client need the database to do?" The key to thinking about the unit is that the database needs to:

  1. take data
  2. process it
  3. produce useful outputs

So start with asking questions like:

The outputs are the key. If you have this sorted at the outset it's going to make your life so much easier later on - trust me on this. And if you have a real client, even a very small one, it'll make coming up with ideas for outputs easier as well.

msword iconThe Unit 3 Brainstorming sheet - for starting to get some ideas together

pdficonBagshaw's Vets - key questions and a basic reminder of a structure

Your database needs to be relational of course, but that's easier than it looks at first glance.

A word about Access:

Access is a Relational Database Management System (an RDBMS). This means that it's a piece of software which controls the creation and management of a database. Access itself is not a database - the database is the collection of data that you enter into it.

Your client probably has Access on their system as part of their MS office suite. That's a good enough reason to use it as a piece of software (you should note, of course, that other RDBMS's exist...).

You should probably look at That Blue Square Blog for all the really good other A Level stuff.