Object–role modeling

More recently ORM has been used to model business rules, XML-Schemas, data warehouses, requirements engineering and web forms.

Nijssen made fundamental contributions by introducing the "circle-box" notation for object types and roles, and by formulating the first version of the conceptual schema design procedure.

Object role modeling also evolved from the Natural language Information Analysis Method, a methodology that was initially developed by the academic researcher, G.M.

[2] In 1989, Terry Halpin completed his PhD thesis on ORM, providing the first full formalization of the approach and incorporating several extensions.

Nijssen co-authored the book "Conceptual Schema and Relational Database Design" and several joint papers, providing the first formalization of object–role modeling.

A graphical NIAM design tool which included the ability to generate database-creation scripts for Oracle, DB2 and DBQ was developed in the early 1990s in Paris.

[4] ORM is attribute-free: unlike models in the entity–relationship (ER) and Unified Modeling Language (UML) methods, ORM treats all elementary facts as relationships and so treats decisions for grouping facts into structures (e.g. attribute-based entity types, classes, relation schemes, XML schemas) as implementation concerns irrelevant to semantics.

By avoiding attributes, ORM improves semantic stability and enables verbalization into natural language.

Fact-based modeling includes procedures for mapping facts to attribute-based structures, such as those of ER or UML.

Example of an ORM2 diagram
Overview of object–role model notation, Stephen M. Richard (1999). [ 3 ]
Example of the application of Object Role Modeling in a "Schema for Geologic Surface", Stephen M. Richard (1999). [ 3 ]