Fig. 8.1.9 is a symbol depicting the Yourdon approach to structured programming and
development.
Fig. 8.1.9 A networked data structure.A while later came the idea of database management systems as a means of logically
organizing data. With the DBMS came the idea of organizing data hierarchically and in a
network. An early hierarchical organization of data was used by IBM's IMS. An early
form of network organization of data was Cullinet's IDMS.
In the hierarchical organization of data was the notion of a parent/child relationship. A
parent could have zero or more children. And a child had to have a parent.
Fig. 8.1.10 depicts a diagram that has a parent-child relationship and a networked
relationship.
Chapter 8.1: A Brief History of Data Architecture