Which database to you query? They're on the blockchain, but you have to know which format you're accepting, how to verify, etc. Do you accept OpenSea as the source of truth for NFT ownership? How about Foundation? What about MyFirstMarketplace, the one that I've decided to create?
This requires some social contract to know who the authority is, and that's probably based on how much they have spent on marketing to become The Authority.
The blockchain is the database. It stores objects and, like postgres, can store code for manipulating the objects. Each NFT would have a particular storage location which you can query, either directly via a block explorer like etherscan.io or via javascript using any one of a number of apis like ethers.js
This sub-thread is talking about an existing case where an NFT has been taken from the person who paid for it by social engineering. The new owner won’t return it so the marketplaces have blacklisted the NFT. So querying the chain isn’t enough in this case because social consensus has determined the chain to be wrong.
The blockchain isn't the database, it's just the storage medium. There are multiple different NFT database on top of the blockchain, implemented in different ways by different people, conforming to different standards.
you missed the part where the parent asked 'who is the authority'
if there are 20 NFT chains, and 10 of them assign ownership to A, and 5 of them assign it to B and the other 5 don't assign it at all - what can we say anymore about the ownership?
all of this public ledger stuff might make more sense if, unlike as is customary, there is a single authoritative chain instead of a 'marketplace' of chains.
it's up to the nft originator to assign ownership in just one jurisdiction. if they create and sell multiple nfts in different venues, but for the same item, then i imagine that would damage their reputation and the value of their prior and future items. the chain itself does not assign ownership independent of the nft originator.
with art i think nfts do function very much like certificates of provenance. game items are different in that the community of players, or the company hosting/developing, indicates the proper database source (chain).
