Given a large collection of structured data, how can you provide an efficient way to gather, retrieve, and update information when you don't know what kind of operations people will need? That's the fundamental idea behind the relational model, invented by E. F. (Ted) Codd. SQL is the most visible implementation of the relational model—a declarative language where you describe what you want, not how to do it. Donald Chamberlin and Raymond Boyce developed SQL based on Codd's ideas.