6. Relational database

To overcome the limitations of a simple flat file database that has only a single table, another type of database has been developed called a 'relational database'.

A relational database holds its data over a number of tables instead of one. Records within the tables are linked (related) to records held in other tables.

The picture below shows two tables. The main one is called 'customers'. This contains almost the same fields as we have seen in the flat file database. But there is one key difference - the city is now held in a separate table called 'city'. The line between them shows there is a link (relationship) between a record in the city table and records in the main table.