Relationship Cardinality Constraints in Relational Database Design

Abstract

Database modelling is a complex task that involves conceiving, understanding, structuring and describing real universes of discourse (UD) through the definition of schemata using abstraction processes and data models. Traditionally, three phases are identified in database design: conceptual, logical and physical design. The conceptual modelling phase represents the most abstract level since it is independent of any database management system (DBMS) and, consequently, it is very close to the user and allows him/her to collect almost completely the semantics of the real world to be modelled.