The BookBrainz schema describes how the data used by BookBrainz is stored. It’s quite important to have a good idea of this before you look at any of our code. If you’re coming from a MusicBrainz background, our schema is similar, but there are some key differences - see Coming from MusicBrainz.
The BookBrainz schema is defined in the python-bbschema package, which you can access at https://github.com/BookBrainz/python-bbschema. When the schema is more stable, there’ll be a nice schema diagram here to help you understand how things fit together, but for now, you’ll have to make do with some words.