This NIP offers a plug-and-play method to export/sync information from existing systems using relational databases into Nostr. It is an application specific type where interoperability with other Nostr apps is not expected.
The `d` tag is used for the row's primary key, the `n` tag places the row into an unbound list to represent the table and the `u` tag references a database name.
Foreign key values should be adjusted to match the corresponding `d`-tag they point to.
Since column names are arbitraryly defined by the data source, such data source might also decide to map certain names to single letters to enable indexing by that column when on Nostr.