User-friendly error message (1 Viewer)

I'm using Access for my GCSE, but am new to it.

In my tables, I want to make it so that the user has to enter data into some fields. How do I do this?

Also, how do I then make my own user-friendly error message appear, rather than the one Access automatically gives?

Many thanks

A common way of validating data is with the before update event of the form:

http://www.baldyweb.com/BeforeUpdate.htm

1. You can add validation rules and then include your own message.

2. you really should only allow data entry/edits via a FORM and not directly in tables or queries.

3. That way you can use the form's BEFORE UPDATE event to validate and return a message to the user BEFORE there is an error and then they can handle it and then validate again and if it is clean just let it go through.