Relational foundations for functorial data migration | Proceedings of the 15th Symposium on Database Programming Languages

In this paper we present a simple database definition language: that of categories and functors. A database schema is a small category and an instance is a set-valued functor on it. We show that morphisms of schemas induce three ''data migration ...

Functorial data migration

In this paper we present a simple database definition language: that of categories and functors. A database schema is a small category and an instance is a set-valued functor on it. We show that morphisms of schemas induce three “data migration functors”, which translate instances from one schema to the other in canonical ways. These functors parameterize projections, unions, and joins over all tables simultaneously and can be used in place of conjunctive and disjunctive queries. We also show how to connect a database and a functional programming language by introducing a functorial connection between the schema and the category of types for that language. We begin the paper with a multitude of examples to motivate the definitions, and near the end we provide a dictionary whereby one can translate database concepts into category-theoretic concepts and vice versa.

ronentk/notion-semble-integration

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Graceful database schema evolution: the PRISM workbench: Proceedings of the VLDB Endowment: Vol 1, No 1

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You can now convert your Notion pages and databases to durable, private, local files.Your data, offline, forever, for free. pic.twitter.com/AOvITLbzWn— Obsidian (@obsdmd) November 22, 2025

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