Is there a name for the following database schema design/pattern? My eventual goal is to find more literature about the subject. Today's cursory net search was too full of generic words to be able pin down the term (if any exists) for this kind of thing:
Fruit (id, farm) Apple (fruit_id, color) [fruit_id => Fruit.id] Banana (fruit_id, length) [fruit_id => Fruit.id] Orange (fruit_id, is_seedless) [fruit_id => Fruit.id] FruitPack (id, destination) FruitPackFruits (fruitpack_id, fruit_id, fruit_type) [fruit_id => Fruit.id, fruit_type => VARCHAR]
fruit_type would be a varchar column filled with values like "Apple, Banana, Orange, Cherry". It's some kind of "poor man's referential integrity". Obviously, one the failures of this kind of design is being able to insert values that don't resolve out to a useful JOIN (ie: there are no cherries to speak of here).
I'm going to take for granted that the schema is a sufficient caricature of some sort of collection of groups of items for the people here.
In closing, the question is... What's this kind of "poor man's referential integrity" called?
PS. I'm not trying to learn about referential integrity. I want to identify this poor design's name and look further into the "let's design a database schema" aspects (ex: pros, cons, opinions, teachings, etc) that have to do with this commonly seen disaster of a schema.
Post-Answer Edit: Added "polymorphic association" tag for future reference.