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Home PictureObject Role Modeling (ORM) is a powerful method for designing and querying database models at the conceptual level, where the application is described in terms easily understood by non-technical users. In practice, ORM data models often capture more business rules, and are easier to validate and evolve than data models in other approaches.

This site features a number of technical papers and articles on ORM, as well as other approaches such as the Unified Modeling Language (UML). Permission has been obtained from the relevant publishers to reproduce these publications on this website, and to make them freely downloadable. If you are unfamiliar with ORM, you may want to first review the ORM in Detail section of this site. Details about upcoming courses and conferences, as well as links to websites with additional ORM publications may be found in the Resources section.

The editor

Dr Terry Halpin is a Professor of Computer Science at INTI International University (Malaysia) and a data modeling consultant. Dr Halpin formalized the Object Role Modeling approach and has authored seven books and over 200 technical papers. Visit the rest of this site to explore various conceptual data modeling topics discussed in his publications.

Dr. Terry Halpin Thanks for dropping in to the Object Role Modeling Website. In addition to the technical papers on Object Role Modeling and other modeling approaches, you can find details about my book, Information Modeling and Relational Databases, information about other resources, and interviews with the press.

Information on this site will grow with time, so please revisit. If you have any feedback or suggestions, please e-mail me at t.halpin@live.com.


Happy reading!

Terry



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Last updated: 2014 June 17 

What's new?

The ORM2014 Workshop will not be held this year as part of the OTM Conferences event. Options for an alternative fact-based modeling event in Europe this year are currently being investigated.

Updated Call for Papers for the ORM2014 Workshop (extended deadlines) (see this page and Resources page)

Added link to the first of a series of articles on logical modeling for the Business Rules Journal (see Resources page).

The Data Modeling Zone conference to be held in Portland, Oregon, October 20-22, includes three presentations on fact-oriented modeling. Two of these are 3 hour workshops, one by Dr Gordon Everest and one by myself, and the other is a one hour presentation by myself. The full program is accessible online from the Data Modeling Zone website. If you register online for the conference, you can receive a 20% discount off the normal registration fee by entering my promotion code "HALPIN".

The ORM 2014 International Workshop will be held October 29-31 in Amantea, Italy as part of the On The Move 2014 Conferences. The Final Call For Papers may be found here.

Links to article 15 and previous articles of Dr Halpin's series on ontology modeling for the Business Rules Journal are now on the Resources page.

The 9th International Workshop on Fact-Oriented Modeling (ORM2013) was held September 11-13, 2013 in Graz, Austria in conjunction with the On The Move Conferences. Slides for the presentations are available from the ORM Foundation Library. Slides for presentations from some previous ORM workshops are also available from the ORM Foundation Library.

Dr Halpin gave a keynote presentation titled 'Fact-Orientation and Conceptual Logic' at the EDOC2011 Conference in Helsinki on September 1, 2011. A video of the presentation is accessible from a link on the Resouces page.

An updated, 6-page summary of the ORM 2 Graphical notation, including examples, is available for download on the Resources page.

The Exploring Modeling Methods in Systems Analysis and Design (EMMSAD) series of annual conferences provide a forum to discuss the latest advances in information systems modeling. Details about the EMMSAD conference as well as resources from past EMMSAD presentations may be found here.

The Resources page now includes a link to the ActiveFacts toolkit.

The Resources page now includes a link to Andy Carver's Website, and a link to a Visio stencil for drawing ORM 2 diagrams that has been significantly upgraded by Andy.

Information Modeling and Relational Databases, 2nd Edition, Cover The 2nd edition of Information Modeling and Relational Databases (ISBN: 978-0-12-373568-3) was published on March 1, 2008. This major upgrade of the earlier edition runs to 970 pages and includes loads of new and updated content. Fully updated to ORM 2 and UML 2 and the latest developments in SQL and XML, this book reveals the true power of semantic data modeling (covering ORM, ER, and UML), as well as addressing business process modeling, relational databases, and other modeling topics such as the semantic web. Here is a link to the book on Amazon.

The first printing of the book included a number of errors, as detailed in the Book Errata.

NORMA (Natural ORM Architect) is a new modeling tool under development that supports the next generation of ORM (ORM 2). Implemented as an open-source plug-in to Microsoft's Visual Studio .NET, NORMA requires at least the standard version of Visual Studio (2005, 2008, 2010, 2012 or 2013). For further details on the ORM 2 graphical notation, see ORM 2 Technical Report 1. A technical preview of NORMA is available on The ORM Foundation as well as SourceForge. Here is an ORM Foundation link to NORMA, and here is a SourceForge link to NORMA.
The NORMA software is currently in the pre-beta stage, but extensive functionality enhancements and user-interface improvements are planned for the near future. Currently the tool supports entry of ORM2 schemas, verbalization of of most constraints, and code generation (for basic constraints) to a variety of DBMSs (including SQL Server, DB2, Oracle, PostgreSQL, and MySQL) as well as class models and XML schema. NORMA is capable of importing ORM schemas entered in Visio for Enterpise Architects, but the diagrams need to be laid out manually. For Part 1 of the specification for automated verbalization in NORMA, see ORM 2 Technical Report 2.

Recent Updates log:
2014 June 17: Added note regarding removal of ORM2014 Workshop from OTM2014 (this page and Resources page).
2014 June 4: Updated Call for Papers for the ORM2014 Workshop (this page and Resources page).
2014 May 24: Added first Logical Modeling article (Resources page).
2014 May 1: Updated book errata.
2014 March 26: Added first Call For Papers for the ORM 2014 Workshop.
2014 Feb 24: Added details about Data Modeling Zone 2014.
2013 Dec 19: Added 15th Ontology Modeling article (Resources page). Updated book errata.
2013 Sep 30: Added link to ORM2013 Workshop slide presentations. Added 14th Ontology Modeling article (Resources page). Updated book errata.
2013 May 28: Updated submission deadlines in Final Call for Papers for ORM2013 Workshop (this page and Resources page).
2013 May 20: Updated Final Call for Papers for ORM2013 Workshop (this page and Resources page). Added 13th ontology modeling article (Resources page). Updated book errata.
2013 March 6: Added 12th ontology modeling article (Resources page) and first Call For Papers for the ORM2013 Workshop (this page and Resources page).
2012 Oct 25: Added 11th ontology modeling article, and updated CaseTalk details (Resources page). Added link to the ORM2012 slide presentations (this page and Resources page). Updated book errata.
2012 May 23: Updated Call For Papers (extended deadlines) for the ORM2012 Workshop. Added 10th ontology modeling article (Resources page). Updated book errata.
2012 March 1: Added first Call For Papers for the ORM2012 Workshop.
2011 Dec 27: Added link to EDOC2011 video (Resources page). Added 8th and 9th ontology modeling articles (Resources page). Updated ORM 2 graphical summary (Resources page). Added details on EMMSAD2012 Conference and ORM2011 Workshop. Updated book errata.
2011 Oct 1: Added program for ORM2011 Workshop. Added 7th ontology modeling article (Resources page). Updated book errata.
2011 Mar 17: Added CFP for ORM2011. Added 5th and 6th ontology modeling articles (Resources page). Updated book errata.
2010 Nov 25: Added CFP for EMMSAD2011, link to ORM2010 slides, and 4th ontology modeling article (Resources page). Updated book errata.
2010 July 9: Added a link to the ActiveFacts toolkit (Resouces page).
2010 June 18: Updated INTI International University details to reflect its upgrading to full university status.
2010 June 11: Updated ORM2010 Workshop CFP with extended deadlines etc.
2010 Mar 16: Added ORM 2 Graphical notation summary (Resources page).
2010 Mar 15: Added details of ORM2010 Workshop, and updated details of EMMSAD2010 Conference. Added 3rd ontology modeling article (resources page). Updated errata for information modeling book.
2010 Jan 2: Added details of EMMSAD2010 and link to ORM2009 slides (this page). Added 2nd ontology modeling article, link to Andy Carver, link to upgraded ORM 2 Visio stencil (resources page). Updated Halpin employment details. Updated errata for information modeling book.
2009 Oct 19: Updated errata for information modeling book.
2009 Oct 9: Added ORM2009 Workshop final program details; added part 1 of paper series on ontology modeling (resources page).
2009 June 24: Updated ORM2009 Workshop CFP to Final Call For Papers, including new due dates; added 7th article on temporal modeling (resources page).
2009 May 9: Updated ORM2009 Workshop CFP to Second Call For Papers, including submission site.
2009 Mar 30: Added ORM2009 Workshop First Call For Papers.
2009 Feb 3: Updated e-mail address (home page).
2009 Jan 18: Updated home page etc. regarding change in employment etc. Added encyclopedia article to ORM in Detail page, and moved an ORM2 article there from Modeling Issues page. Added 3 workshop papers to Modeling Issues page. Added 2 journal articles to Resources page. Updated conference data on Resources page.


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All diagrams on this site were created with Microsoft Visio.