Add each product once

Hello, can you help me? is there any way I can make OC add an item to the cart once? For exaple, each time the add to cart button is pressed, OC checks if that product is already added, if it is, then it doesn't adds it again.

I need this so that I can sell items once, since they are all different.

Edit:
Or even better, don't let the cart add more items than the ones in the stock.

hi,
i think in simple words you meant to say that similar product should not be added again ? like say laptop is a item from electronic category than if its added once it should not be possible to add it again in cart ?

Well, it's for an art website, each painting is unique, so I can't sell many of the same, just one.