I want to understand how I can difference two request which were rised at the same time??
for example:User A want to buy some product and this product has price for example 100$, this User has only 110$ and increase price to 110$ but at the same time another User B increases price too, and his request postback faster than User A, because A has Slow internet...When A's request at last reaches to the server price is already changed and it's 110$ because of B and after that it will be 120$...
sorry for my English :(