The requirements definition of the data view includes a description of the semantic data model of the area of consideration. In line with the breakdown approach stipulated by ARIS, the description covers both the objects that specify the start and end events of a process chain and the current state of the relevant process chain environment.

Unlike function modeling, data modeling is particularly demanding as far as the method is concerned. In the function view, the only object examined is the function. Furthermore, relationships between functions simply illustrate superordination or subordination.

Chen's Entity-Relationship Model (ERM) is the most widely used designing method for semantic data models (see Chen, The Entity-Relationship Model, 1976). This modeling method uses a variety of specialized terms, such as entity type, relationship type, attribute, etc. The relationships that exist between these objects are numerous and - compared with function modeling - significantly more difficult to classify.

The following pages introduce modeling with entity relationship models (ERM). First, the objects and relationships of Chen's base model are explained. Then, another chapter describes several rules that were added later to the base model.