3. Why use a database?

Reason 3: Information can be extracted from the database and exported as a file.

Most official (or spam) letters that you receive will be personally addressed to you. They have your name, your address, your account details and perhaps even information about things that you have previously bought.

All of this is done by running a query on a database and finding a set of records which match a set of criteria, for example, 'everyone who lives in Birmingham and who purchased something in the last month'.

The data from the query is then automatically extracted from the database and placed into a pre-written letter, merged, printed and sent to you. This technique enables companies to contact thousands of people very quickly.

Reason 4: Visualise and summarise data. Queries and reports can be produced from the stored data

Queries on a database can result in a huge amount of results being returned. These results are initially shown as a list of records in a table. Whilst tables can be sorted into a logical order it can be hard to spot trends or patterns and a table isn't really the best way of presenting data to other people.

Instead, reports can be created from the records returned by the query. A report will enable the information to be presented in a more professional way with graphs, labels, annotation and your company logo.