Checking field for duplicates

[Trazzel]

How does one check to see whether or not a duplicate PIN ID number has been entered into the text box field, send a message "A duplicate number has been found, please choose another", check that number for any duplicates and if all is OK, move on.
The program I wrote sends a message for every number that is entered AND allows for the user to tab right through a duplicate number.

Thank you

 

[jrbarnett]

If the textbox is part of a bound form, then set the field to require unique values in the table design (or make it the primary key).

John