draw a use case diagram for the following situation Stillwater Antiques buys and sells one-of-a-kind antiques of all kinds. Each item is uniquely identified by an item number and is also characterized by a description, asking price, condition, and open ended comments. Stillwater works with many different individuals called clients, who sell items to and buy items from the store. Some clients only sell items to Stillwater, some only buy items, and others both sell and buy. A client is identified by a client number, and is also described by client name, and client address. When Stillwater sells an item in stock to a client, the owner wants to record the commission paid, the selling price, sales tax and date sold. When Stillwater buys an item from a client, the owner wants to record the purchase cost, the date purchased and condition at the time of purchase.

Answer 1

I really don't see the challenge here, you have a purchase (with purchase orders), and a sales receipt (with a sale receipt). Both use the same data system.
It is beyond my understanding why (for legal reasons) you don't record the condition when sold to a client.

If it were my business, I would also like to have the ability to produce current inventory sheets.