Yes thats the same idea.
With what I have done is literally the delete button is not there for any Brand (in your case Category) that has an associated item.
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.