Ontologies are systems for recording knowledge in a general form so that it can be reused and distributed1 Gómez-Pérez, Asunción; Fernández-López, Mariano; Corcho, Oscar (2004):Ontological engineering. With examples from the areas of knowledge management, ecommerce and the Semantic Web. London, New York 2004. .

There are various approaches to structuring ontologies, which possess different explanatory power and argumentative strength depending on the task and the knowledge to be processed. Therefore, the task-oriented selection of a suitable type of ontology is necessary.

A distinction is made between frames, first- and second-order logic, semantic networks, and description logic.

The Frames approach allows the capture of a hierarchy of classes, subclasses with their own or inherited attributes and associated values. For example, the class "Clothing" can have an attribute "Color". The subclass "Shirt" will then also be presumed to have the attribute "Color". If an additional attribute "Collar Type" is introduced in the class "Shirt", then both "Color" and "Collar Type" will be presumed to be inherited attributes in the subclass "Field Shirt".

In other logic ontology approaches, functions and axioms are introduced that allow functional relationships to be represented. This allows, for example, assumptions about the dependency of variables such as sales volumes and prices to be recorded in the ontology.

The semantic network approach is based on representing knowledge as a graph of labeled nodes and connections, where the nodes represent the concepts, instances or values and the connections describe the relationships between them 1 Gómez-Pérez, Asunción; Fernández-López, Mariano; Corcho, Oscar (2004):Ontological engineering. With examples from the areas of knowledge management, ecommerce and the Semantic Web. London, New York 2004. . The types, application areas, and general advantages and disadvantages of semantic networks compared to other ontology approaches - here .

The approach of “ Description Logic ” or description logic originates from semantic networks 3 Köhler, Andre(2010): Intelligent Data Interchange. InterventionsfreierGeschäftsdatenaustausch durch Wissensrepräntation und ontologisches Matching.Wiesbaden 2010. . In this, classes (“TBox”) are extended by instances (“ABox”)1 Gómez-Pérez, Asunción; Fernández-López, Mariano; Corcho, Oscar (2004):Ontological engineering. With examples from the areas of knowledge management, ecommerce and the Semantic Web. London, New York 2004. . The above example can be supplemented in the description logic by the distinction between "A shirt" and "The shirt" .