Many to many between lots of tables? TL;DR: How could I set up many-to-many relationship between that many tables and is it viable/recommended?


Each body type has its own table
Each car in each body type table can has several features




As you can see from my "schema", each car can have several features but I need to connect features table to several car body types tables (many to many relationships). I've thought about it for several days but Im still not sure how to achieve this.

Why all body types are in separate tables? This seems to follow normalization rules, it should also speed up queries because I will never have to query several body types at once.

Is it possible or should I rethink it? Should I just make another table about body types and combine all the cars? I expect to have a maximum of 1M entries (all body types combined). There's going to be a lot more reads than writes.
Create a supertype entity CarBody for subtypes Sedan, SUV, ... and move all general information to that supertype. Your M-M relationship will be between CarBody and Feature. See this topic for subtyping in datamodeling Supertype/Subtype deciding between category: complete disjoint or incomplete overlapping .