How to use command only once VK Api python?

Question

Python

However hello! I've been racking my brains for about 5-7 hours, I can't figure out how to make the command be used only once, since I'm implementing a game bot (Not on VkLongPoll). In general, I wanted to add promotional codes, everything seems to work, the balance is counted, but there is just this nuance, this command can be used many times.
I use these libraries:
DB - Sq3lite, random, datatime, vk_api.
If you need a piece of code, I'll throw it off.
PS Since this is the case, tell me how to check id. Just my average knowledge is not enough

Answer 1

In the database, create a field where you save the promo code, upon activation, check whether the user has a promo code, if so, reject it, if not, accept and add the promo code to the field.