What is a Database?

Database is a term that means different things to different people. That's if you know what one is at all, quite often there seems to be an assumption that someone will know what a database is, and human nature being what it is, no-one wants to look foolish and ask.

I suppose one of the earliest forms of a database is a card file, and its certainly a useful metaphor to help explain what a database is. With a card file data is written onto bits of card, perhaps it will be a contacts name, address and phone number or maybe details of different products, either way the card will then be stored in a file which is normally sorted alphabetically or numerically depending on the nature of the data.

Microsoft Excel can be used as a simple database, very much like our card file. In this case the individual spreadsheets within a workbook would be the file while each row would represent a card. We can also give the columns meaningful headings such that a name could be stored in one column, the first line of the address in another, the town in a third, county in a fourth, postcode in a fifth and phone in a sixth. Unfortunately there are downsides, as the amount of data increases so finding something useful becomes more difficult and like a card file there's no formal way of ensuring that a name (or something like a name) is entered in the right column.

Database software can take things a step further in that we can more formally define the data to be collected, and apply rules to the sort of data that should be collected. We can also create custom front ends to create and maintain the data which can be extremely simple, or very sophisticated, applying more rules to the data before its saved to the database, or maybe it would be something in between. We can also make better use of the data, by generating reports we can start to gain more meaningful business intelligence from our data. Another important feature of database software is the ability to secure the data, its not always appropriate or advisable for every employee to able to see all the data, particulary when legislation such as the data protection act is considered.