This article explains how to use validation rules and validation text in table fields and form controls.A validation rule is one way to restrict input in a table field or a control (such as a text box) on a form.One idea I had was for validating whether a customer stored in the database is in fact old enough to be purchasing the games in their order, so I wrote a little PHP function to do just that.
Validation text lets you provide a message to help users who input data that is not valid.
When data is entered, Access checks to see whether the input breaks a validation rule – if so, the input is not accepted, and Access displays a message.
The steps in the section Add a validation rule to a control on a form, later in this article, explain how to add rules to the properties in individual controls.
Your validation rules can contain expressions — functions that return a single value.
The most recent college project I’ve had is to develop a system for a video games shop.