Entities and relationships

An entity is a business object with an identity and typed properties: an account, invoice, person, shipment, policy, or request. A relationship connects two entities with a named, directional meaning such as billedTo, ownedBy, or coveredBy.

Model relationships when a decision requires the connection, not just a lookup. “Which invoices are overdue?” needs invoice properties. “Which strategic accounts have overdue invoices?” needs an account-to-invoice relationship and an agreed definition of strategic.