a simplified bookstore structure from the rails guides.
https://cdn.masto.host/rubysocial/media_attachments/files/110/723/941/698/609/529/original/5eb82da1d7afb098.png
Nothing wrong with this as an example, but, having spent almost every day since Jan 2011 writing a bibliographic metadata management system, it does make me laugh when people use the "bookstore" domain as a modelling example.
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