The language table is real, and is missing from this diagram
film.language_id is a NOT NULL foreign key pointing at language, meaning every film row must reference a valid language. The table exists in the live schema and carries data. It was missing from the original published diagram and is omitted from this redraw for the same reason it was likely left out originally: it hangs off film with no further relationships, so it adds a node without adding structure. That's a choice worth naming rather than quietly making.
Three columns look like foreign keys but aren't enforced
staff.store_id, inventory.store_id, and customer.store_id each reference store in practice, but Postgres carries no FK constraint behind any of them — the schema will accept a value that points nowhere. This is a quirk of the Sakila sample database design, not something introduced by this analysis. These are omitted from the diagram because their absence from the constraint system means there's nothing architectural to show — just a convention the data happens to follow.
