This paper first appeared as chapter 4 of the following book: Bernus, P., Mertins, K. & Schmidt, G. (eds.) 1998, Handbook on Architectures of Information Systems, Springer. Details on this publication are available from Springer's website
Object Role Modeling (ORM) is a method for modeling and querying an information system at the conceptual level, and mapping between conceptual and logical (e.g. relational) levels. ORM comes in various flavors, including NIAM (Natural language Information Analysis Method). This article provides an overview of ORM, and notes its advantages over entity relationship and traditional object oriented modeling.
This paper and the Object Role Modeling Overview paper overlap substantially; however, the historical details, symbol summary, and references provide additional material.