On page 350 in the PDF it mentions that having multiple tables have a
has_one relationship to the same table cannot work, that is,
I quote, “We can’t possibly arrange to have the foreign key in the
catalog entry point back to all three tables”
If I understand correctly, it says catalog_entry cannot contain a
reference to all three tables. My question is, why not?
If catalog_entry has two foreign keys, image_id and sound_id, wouldn’t
all the following calls work?
I cannot see the problem the book suggests is there, what am I missing?