Conceptual and ontological aspects of the plurality of ancestors in "entity-relationship" information models

The design of information models in the development of automated systems involves constructing entity-relationship models, which define classes of entities and interclass relationships of the ancestor-descendant type, serving as a conceptual and ontological foundation for the subsequent creation of databases. This article explores aspects of representing the semantic constraints of the subject area imposed on relationships between entities in entity-relationship models. A special type of relationship between classes of entities, termed multiple ancestor (MA) relations, is highlighted, where several instances of the ancestor entity may exist for a single instance of the descendant entity. The article analyses the possible semantic constraints that arise in such cases and the anomalies they generate. Based on the introduced concepts of ascending kinship lines and the MA predicate, a formalisation of MA integrity is presented. Examples of formal MA constraints are provided, including positive (requiring the coincidence of ancestor instances), negative (requiring the mismatch of ancestor instances), and mixed. The mutual influence of several MA constraints with partially intersecting lines of ascending kinship is also examined. Finally, the feasibility of implementing MA constraints in relational database models is evaluated.