Functorial Data Migration
Database management is a huge industry, yet logical database design remains problematic. While the relational algebra is sufficient to understand single tables and operations that can be performed on them, it has no means to capture the structure of the database as a whole. The idea presented in this paper is that databases can be modeled by elementary category theory: A schema is a category C and database state on that schema is a functor C ?? Set. This categorical understanding can be considered a new denotational semantics for databases.