Date/Time Stamp on barcode input form

[computersnack]

I have a barcode input form. When a barcode is scanned, the value of the barcode, along with a date/time stamp using the now() function (hh:mm:ss) is entered into a table in the database as 2 separete columns. I need to make sure that I don't have any 2 barcodes with exactly the same date/time. They must be at least 1 second apart. How can I easily make this happen? I can't control how many times the barcode actually gets scanned. Any ideas? Thank you.

[June7]

One way is to set the two fields as unique compound index. Access won't allow duplicate and will message the user.

Otherwise, use code to lookup the combination in table.

I should think it extremely unlikely the same barcode will be scanned more than once per second. So maybe the intrinsic feature will be sufficient for those rare instances.

[computersnack]

One way is to set the two fields as unique compound index. Access won't allow duplicate and will message the user.

Otherwise, use code to lookup the combination in table.

I should think it extremely unlikely the same barcode will be scanned more than once per second. So maybe the intrinsic feature will be sufficient for those rare instances.

Well, that would work except I don't want it to message the user. Also, it is possible to scan more than once per second because I can simulate it on a keyboard by pressing a key multiple times. And also I plan to have multiple barcode scanners.

[June7]

But in reality, how will the scanning take place? User has to pick up item, find the bar code, click button on wand or pass item over a scan table?

Maybe VBA error handler code can capture the error triggered by the index violation. Otherwise, code in the form BeforeUpdate event to search table for the combination.