For more information about data types, field sizes, and input masks, see the article Introduction to data types and field properties.
You can define validation rules for table fields and for controls on forms.
The truth is that none of us filling in forms — there is a lot of evidence to show that users get annoyed by forms, and are one of main things that will cause them to leave and go somewhere else if they are done badly. We want to make filling out web forms as non-horrible as possible, so why do we insist on blocking our users at every turn?
There are three main reasons: In the real world, developers tend to use a combination of client-side and server-side validation, to be on the safe side.
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.For example, if you use HTML entity encoding on user input before it is sent to a browser, it will prevent most XSS attacks.However, simply preventing attacks is not enough - you must perform Intrusion Detection in your applications.If so, it allows it to be submitted to the server and (usually) saved in a database; if not, it gives you error messages to explain what you've done wrong (provided you've done it right).Form validation can be implemented in a number of different ways.