Applied ICT A Level Unit 3 - Database Design
Databases 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.
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.
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:
- take data
- process it
- produce useful outputs
So start with asking questions like:
- who will use the database?
- what will the database produce?
- how will it display this information? On screen? On paper?
- who will use the outputs? The client? Their customers? Someone else?
- how often is each output going to be required? Once a day? Once a week? When will they be needed?
- how often will new data be added to the database? Who will add it? What will be added?
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.
The Unit 3 Brainstorming sheet - for starting to get some ideas together
Bagshaw'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...).