Break Up Book Into More Entities

I was looking at the data in one of the MySQL variants and noticed quite a bit of data duplication in authors and publishers. I wondered if it would be worthwhile to remove that duplication by promoting authors, years, and maybe even publishers, to full-fledged entities.

This is the original schema, where authors are simply listed on the Book entity.

And here is a version with separate entities for authors, years, and publishers.

The separate entities allow us to navigate to the books by the same author, or at the same publisher, or from the same year. We can already achieve something similar with search terms, but would the extra complexity be worth the small improvement in features?

Probably not.

The goal of this project is to have something substantial to explore different relationships in various tech stacks without it becoming overwhelming. Representing lists of primitives can be an interesting challenge on its own. The relationship of Book to Title models a classic association between entities. The relationships of Book to authors and years is that of an entity to atomic types. They provide an opportunity, within the frame of the exercise, to explore how to implement different kinds of data relationships.

I’m using PlantUML for the class diagrams.