Entity Relationship Diagram

The Entity Relationship diagram (ERD) is a high-level data model that shows the major entities and relationships, which support a wide business area. An ERD is primarily a presentation or discussion model.

The ERD objective is to provide a view of business information requirements to satisfy the need for broad planning for development of its information system. These models are not detailed (only major entities are included), and not much detail, if any, on attributes. Many-to-many (nonspecific) relationships are allowed, and keys are generally not included.