How Can We Represent Binary Relationships?
In this section, we examine how each of the specialized record relationships—trees, simple networks,
and complex networks—can be represented using linked lists and indexes.
A Review of Record Relationships
Records can be related in three ways. A tree relationship has one or more one-to-many relationships,
but each child record has at most one parent. The occurrence of faculty data shown in Figure H-12 illustrates
a tree. There are several 1:N relationships, but any child record has only one parent, as shown in
Figure H-13.
A simple network is a collection of records and the 1:N relationships among them. What distinguishes a
simple network from a tree is the fact that in a simple network, a child can have more than one parent
as long as the parents are different record types. The occurrence of a simple network of students, advisers,
and major fields of study shown in Figure H-14 is represented schematically in Figure H-15.