In [Spi], we developed a category of databases in which the schema of a database is represented as a simplicial set. Each simplex corresponds to a table in the database. There, our main concern was to find a categorical formulation of databases; the simplicial nature of the schemas was to some degree unexpected and unexploited. In the present note, we show how to use this geometric formulation effectively on a computer. If we think of each simplex as a polygonal tile, we can imagine assembling custom databases by mixing and matching tiles. Queries on this database can be performed by drawing paths through the resulting tile formations, selecting records at the start-point of this path and retrieving corresponding records at its end-point. Contents
David I. Spivak