Friday, September 15, 2006

A Traffic fines database!

You're currently employed as an IT support person at the local police station, and you nearly fall over when you are asked to do some data entry, only to find the following "database" being used to record traffic fines!?

DriversLicenseID FineType IncidentLocation DriverName FineAmount Reporting officerDate
26545LD Speeding
(-15)
Springwood Harry Potter $350 Jenny Rainer 12/5/05
65475TN RedLight
Katoomba Bob Smith $200 Jeff Skillset 15/5/05
75163LD Speeding
(15+)
Lawson Rachel Rogers $350Nadia Smith20/5/05

What's wrong with this database? Can you see how it might be possible to enter inconsistent information? (Unfortunately I can't get the whole table to display, but there should also be a "Reporting Officer" column and a "Date" column).

We'll see if we can design a new database that is more efficient and consistent!

Over the past few weeks, we've been practising the task of improving database tables by breaking them down into smaller tables with relationships. The technical term for the process that we've been practising is Normalisation. It's probably a good time now to find out a bit more about Normalisation as we tackle our Police Fines database. After a break, take 10mins to read this useful Microsoft Knowledgebase article: Database Normalization Basics. We'll go through the example there together, discovering 1st, 2nd and 3rd normal form.

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