Hi all,
Looking for some feedback on this idea. My solution seems awfully complicated to me, wondering if anyone can point out a better method of doing this.

Im trying to borrow eBay's method of listing items with specific related attributes, called "Pre-filled Item Information" - for instance when you want to list an iPod for auction, it prompts specifically for model number, hard drive size, etc. and stores the user values with that particular listing. This will help with searching and to keep the data cleaner. For each item available to list, I will be storing its specific parameters and values for each parameter.

My solution attached, read it starting from Listing entity - either way

You will notice ListingParam is related only to Param and not Enum. This is because I will store the value as text, not a foreign key.

Thanks