Functorial Data Migration

In this paper we present a simple database definition language: that of categories and functors. A database schema is a category and a state is a set-valued functor. We show that morphisms of schemas induce three "data migration functors" that translate states from one schema to the other in canonical ways. Database states form a topos of which the classical "relational algebra" is a fragment. These ideas thus create a new denotational semantics for database theory. Contents

• Type: Journal
• Year: 2010
• Where: CORR
• Authors: David I. Spivak
• Keywords: CORR 2010, Database, Education, Functors, Simple Database Definition