That could be tracked fully on a blockchain with the added advantage of no longer needing to trust some centralized office to 1) correctly track ownership and 2) properly store their records.

A similar idea exists for tracking ownership of domain names.

There are other cases where you trust the oracle but want some form of non-equivocation. A nice example is a notary. In that case, just an SQL database doesn't suffice. Sometimes, something like a pgp-signed statement could work for that.

If you want some more resilience against the claim 'that was signed with a fake key' you could mandate all signatures be published on an actual block-chain. This time-stamps them so you can see whether they happened before a key compromise, and allows the requirement that the counter-party audits the blockchain to ensure that no signatures are published that they did not know of. This audit would mean that signatures published with a compromised key would quickly be detected.

This way, the records of the notary are publicaly checkable. You now only need to trust the notary at the time of publishing their signature on the blockchain (with some extra time to ensure they can't claim to not have audited yet).