I'm having trouble with the following:
I'm working with authors, books, contracts, and payments.
Authors to books is a many to many relationship, as is books to contracts. Contracts to payments is a one to many relationship.
Some of the payments are in contracts that involve more than one book, yet the payments are book specific. So an author might have written The Iliad and The Oddyssey, get a single contract for both books, yet be paid on the delivery of each specific book. This works fine in most cases, however I noticed that in cases of more than one author, the author ids appear once for each book in the contract (rather than the payment). This is in a layout based on the "royalties table", and displaying records from the "book author link" table.
So in a nutshell I'd like to relate a contract to more than one book, and relate a number of payments to that contract and specific books related to the contract.
I hope that makes sense?
Attached is a diagram of what I believe are the relevant tables.