What is a validation rule?

Answer 1

In a database it is important that data is put in accurately. One method of doing that is to use validation rules to restrict what people can put in. So you might have a school where children have to be over a certain age before they can join. You could build a validation rule to ensure they meet that requirement or to ensure that the person entering the data does not make a mistake when entering it. A validation rule will stop them making an error and with the Validation Text, it will give them a message telling them what their error is.

Answer 2

A validation rule in a database is a rule that prevents the entry of unwanted data. In Microsoft Access for example, a validation rule might prevent someone entering a phone number that is too short or a first name that contains special characters like # and @.