I helped build this system for a major ticketing company. We used a database, that was it - because its pretty simple overall when you're taking a cut. Confirm

I helped build this system for a major ticketing company. We used a database, that was it - because its pretty simple overall when you're taking a cut. Confirm original barcode, mark transaction, issue a new barcode. At performance time only the new barcodes work, and if you didn't get it through the ticketing company then you were just out of luck.