Are we dealing with Access? You did say database. If Access, then is it a form or datasheet? If a form, is it a single record form or a continuous form. Asking all this because the only form where you can change the color would be the single record form. Where you can change the background color on the other forms, ALL records receive that color change, not just the current record.
So, if it is a single record form, then in the AfterUpdate event, this code should do the trick:
Me!fldName.BackColor = xxxxxx (where xxxxxx is the color you want.)