Ask HN: How Airtable / Notion's Database is implemented?

Both Airtable and Notion, along with numerous no-code tools, create their own interpretations of "tables". In these tables, you can define inter-table relationships, make columns unique, and so forth, much like real tables.

These tools likely don't permit users to directly manipulate an actual database table. Therefore, I believe they adopt alternative approaches.

My hypothesis is that they might utilize NoSQL databases and treat each row as a discrete item.

However, ensuring reference consistency without using real table features might be very challenging. Some tools offer a "calculated column" feature, which stores the results of complex functions that take the results of referenced tables as input. Caching and data change notifications might do the job, but is it really feasible?

Furthermore, I suspect that performance might be severely degraded in such an architecture if the number of rows grows significantly.

Any thoughts?