I've only been using Access for six weeks and have learned quite a bit. I just successfully created a form that will be used by about six people and I want to have one of the controls to have a validation rule. They will be entering a code number from a list of about 50 and I want to make sure that they can't make a keying error. I thought 50 options might be cumbersome in a combo box but I'm not sure. I don't know how to write the validation rule. I also want to format a different control box so that the keyer is required to fill in the box. How do I do that?