Unique Voucher Codes

We just started to use EShop's voucher feature for gift certificates. Although we create the voucher codes using a 6 character random text string generator, there is the possibility (however slight) that duplicate codes will be issued and cause confusion at a later time. It would be nice for EShop to disallow duplicate voucher codes.

The same would apply to coupon codes.

Hi Steven,
Thank you for suggesting on this. It is useful. I made the Unique check for coupon and voucher. Please update EShop again to have that feature.
Sincerely, Giang