The database is made up of ‘records’ each of which contain different categories of information called ‘fields’. For example, a database containing student details would contain a ‘record’ for each student which included ‘fields’ such as name, address, courses taken and exam results. Each record in the database is unique. The records are stored in a ‘table’: each row contains information about one record and each column contains one field of information. For example, in the table below each row contains a film which is one, unique record, and each column contains details of a particular aspect of that film (fields).
 

It is the fields which enable you to interrogate and analyse a database. For example, one could use the above database to search for all films produced or directed by a particular individual or in a particular year. In order to search for films in which a particular actor starred, you would need to add a further field or table containing that information and which had a common field with this table.

A database compiled from a number of tables whose fields can be linked is called a ‘relational database’. For example, if you had a database containing a table as above and another table containing details of actors in each film, you could link the tables and search for films in a particular year with a particular actor, or search for films where an actor worked with a particular director. The more complex or comprehensive the database, the more complex and interesting are the analytical questions which can be asked of it. Most modern DBMSs are relational.

A DBMS therefore enables you to store large quantities of information in such a way that they can be managed and accessed easily. It is also a very flexible way of storing data which can be easily updated. In addition, the DBMS can perform basic calculations on a database containing figures.
 
 

 
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(c)R. Middleton 1997. Last modified 30 June 1998.