The most basic form of databases is the flat file database. This is where data is stored as a single table. Data structured in this way must be, through its very nature, be fairly simplistic. The data can be stored, very simply, using a serial file. Consider an address book for an email package. Most people would assume that there would not be a database driving this. However an important point to note is that any structured data is considered to be a database.

As such we may store the following for each contact.

• Email address
• Forename
• Surname

Each contact will have this information filled in. Consider the fact that we will have 5 contacts. We could have a database like this -

This could then be turned into a serial file without too much issue. Flat file databases do not have a specific way of storing their information. For example we could store the above data in an indexed sequential file with the key as email address. What is common between them is that all of the data is simple and does not have many relations in it. Relationships between related data are much better stored in other databases.