[eigenvalue]

There is a JSON column type in SQLite now, and it's supported by SQLModel/SQLalchemy:

https://www.sqlite.org/json1.html

[bb88]

There's a JSONB column type in postgres for a while now too with the arrow syntax.

I think my point is that the structure of the data in a relational database is tree-like. Yet we can only get tabular data out of the queries.