2. Simple Object Families
As we shall see later in Chapter 6, theObject Model refines a number ofobject families, and each object family may include bothindividual objects andgroups of objects.
The first stage in the development of theObject Model involves the identification and definition of a set of fivesimple object families. As indicated in proposition 2.0.1,simple objects are ones that can be defined without reference to any other object. For example, aperson is a tangible object that can be defined and referenced without reference to any otherperson, but apurchase order is an intangible object that can only be defined in terms of at least 3 other objects, namely aseller, abuyer and aproduct.
| 2.0.1 | Asimple object is one that can be defined and referenced in its own right, without reference to any other object. |
| 2.0.2 | There are fivesimple object families; theaction object family, thelocation object family, thetime object family, theresource object family and theparty object family. |
Hence, proposition 2.0.1 explicitly excludes objects that represent relationships between two or more objects. In theObject Model thes
