Incorporating object relationship notation (ORN) into SQL

Entity-Relationship (ER) Diagrams are widely used in information requirements analysis and database modeling and capture much knowledge of relationship semantics. Even more such knowledge is captured when ER Diagrams are extended with Object Relationship Notation (ORN). Unfortunately, however, much of the relationship semantics expressed in ER Diagrams are not directly translatable into the Structured Query Language (SQL), and, therefore, the implementation of these semantics in relational database management systems is made difficult. In this paper we demonstrate the feasibility and desirability of incorporating ORN into SQL to address this problem.