Link

A link is an object that defines a one-to-many relationship that exists between two business components. It makes master-detail views possible. A master-detail view is a type of view that displays one record of the parent business component with many records of the child business component that correspond to the parent, such as, for example, where a single account includes many contacts. You can use a pair of links to create a many-to-many relationship. For more information, see About Links.