Input mask or vba code that prevents exact duplicate data entries on a form

[wedd]

Hi experts,

Is their an Input mask or vba code that prevents exact duplicate data entries on a form...I've created forms that have date selections from a calendar, drop down list, customer numbers, textboxes for first names and surnames: however, I would like to prevent the user from entering duplicated bookings for a customer; if a customer has been allocated a time slots, a date of their booking etc...if the user tries to enter a booking that has already been saved...a pop up message will display that it isn't possible to enter the same details of books and dates because it has already been booked for another customer. Can this e done? If so, would you have any great examples of how it is done on perhaps a sample database or a database with code you may have developed yourself?
I am a beginner/intermediate code writer of visual basic...so this will be a great help in my learning...


Thanks for your contributions :friends:

[HiTechCoach]

See: Clashing Events/Appointments (http://www.hitechcoach.com/index.php?view=weblink&catid=78%3Aaccess-dates-tips-and-tricks&id=500%3Aclashing-eventsappointments&option=com_weblinks&Itemid=23)