Preserving Relationship Cardinality Constraints in Relational Schemata

Abstract

This chapter is devoted to the study of the transformation of conceptual into logical schemata in a methodological framework focusing on a special ER construct: the relationship and its associated cardinality constraints. The section entitled “EER Model Revised: relationships and cardinality constraint” reviews the relationship and cardinality constraint constructs through different methodological approaches to establish the cardinality constraint definition that will be followed in next sections. The section “Transformation of EER Schemata into Relational Schemata” is related to the transformation of conceptual n-ary relationships (n³2) into the relational model following an active rules approach. Finally, several practical implications as well as future research paths are presented.