When designing systems, the interface between Data Services and Systems Development is the entity object diagram. It may be referred to as the Entity Object, Business Object or other term. This is the Business System Analyst's view of the entity object (entity bean). It represents the denormalized view of the data objects required by the control object. It is often a combination of inverted list and hierarchical structures. The arrows show the location of the foreign keys as attributes, not part of the primary key of Product. The Business Object represents the design requirements for the API. Typically, there will be many of these models produced to update and query persistent data within a project.

The diagram also shows the hierarchical way process people see data. One brand has many products. One product has many parts. One package is used to ship many products. This view reflects the requirements of Sales and Marketing. In reality, the world is many-to-many. A brand has many products, but a product may be sold under many brand names. A product has many parts, but a part may be used in many products. A product may be shipped in many packages, but a package may be used to ship more than one product.

The world is many-to-many!