Object Relationship Notation (ORN) is a declarative scheme that allows a variety of common relationship types to be conveniently specified to a database management system (DBMS), thereby allowing their semantics to be automatically enforced by the DBMS. ORN can be integrated into any data model that represents binary associations or DBMS that implements them. We give a brief description of ORN syntax and semantics and provide algorithms that can be used to implement ORN. These algorithms must deal with the presence of association cycles in the database. We explore in detail the problems caused by such cycles and how ORN and its implementation deal with them, and we show that ORN semantics are noncircular and unambiguous.

Object Relater Plus is a practical tool currently being used for research and development of enhanced object databases (ODBs). The tool, which is a prototype object database management system (ODBMS), provides two languages that are compatible with the ODMG-93 ODBMS standard yet enhance it in some significant ways. The Object Database Definition Language (ODDL) allows object relationships to be better defined and supported; provides for the specification and separation of external, conceptual, and internal views; and facilitates the implementation of domain specific ODB extensions. The Object Database Manipulation Language (ODML) augments ODDL by providing a C++ interface for database creation, access, and manipulation based on an ODDL specification. We give an overview of Object Relater Plus, emphasizing its salient features. We also briefly discuss its architecture and implementation and its use in developing scientific databases.