Comprehension of Hierarchical ER Diagrams Compared to Flat ER Diagrams

HERD is a semi-algorithmic method for creating hierarchical ER diagrams from bottom up. The method is based on packaging operations that are applied in several steps on a given flat ER diagram. The result is a hierarchy of simple and interrelated diagrams (namely ER structures) with external relationships to other such diagrams. This chapter describes the application of HERD method using an example from a hospital domain, and an experiment in which we compare the comprehension of HERD diagrams with flat ER diagrams.