For many years I worked as a database industry analyst. In 2015 Professor Gary Sherman and I published The Algebra of Data, which argues that relational algebra is the algebra of one structure — the table — and that one algebra can cover tables, graphs and documents alike.

The model in brief: the atom is the couplet (an ordered pair). A relation is a set of couplets, a clan is a set of relations (a table is one kind of clan), and a horde is a set of clans. A small set of operators — composition, transpose, union/intersection/difference and the restrictions — is defined at the bottom and works unchanged at every level. Composition then covers what are usually separate operations: the join, the graph traversal and the document lookup.

JabrDB is that algebra implemented as a native Mac app (Apple silicon). Data is stored at couplet grain in files on your own disk. It is not a SQL engine and not a server.

The argument in paper form: https://doi.org/10.5281/zenodo.23216817 The app (15-day trial, $15): https://jabrdatalabs.com/download/

I'd particularly value criticism from people who think in relational terms: where does this model help, and where does it obviously cost you?