2. Validation

When you are entering data into a database or spreadsheet, it is vital that the data is as accurate as possible. 

You have probably heard the term Garbage In, Garbage Out (GIGO).  Basically it means, if you put data into your database with lots of mistakes and errors, then when you need to search for some data, the results that you get back will contain lots of mistakes and errors i.e. rubbish!

Validation techniques can be used to try to reduce the number of errors in the data being entered.

The validation is performed by the computer at the point when you enter data.  It checks the data against the set of validation rules which you set up when developing your new database or spreadsheet system.

DEFINITION: Validation aims to make sure that data is sensible, reasonable and allowable.

It is critical that you understand what this definition means and can repeat it when asked in an examination question. 

Students regularly say in exam answers that ‘validation checks that the data is correct’.  It does NOT!!  If you enter ‘Smithe’ instead of ‘Smith’ or ‘07/08/07’ instead of ‘08/07/07’ no amount of validation in the world will pick up that human error.

So while validation can help to reduce the number of errors when entering data, it cannot stop them – be very clear about that.