
4.2 Fact Types
In ORM, a relationship type used to identity an entity type is called a reference type (e.g.,
Country has CountryCode). Other relationship types are called fact types (e.g., Country com-
peted in Sport
). Relationship types are also called sentence types or associations. In the
Visio tool, all sentence types are informally called fact types, or simply facts.
You can add sentence types to an ORM model by entering their text into the Fact
Editor. You can also add them graphically, by working with Object Type and Predicate
shapes in the drawing window. You can edit existing sentence types using the Fact
Editor or Database Properties dialog, ...