Object–role modeling

Not to be confused with Object-relational mapping.

example of an ORM2 diagram

Object-Role Modeling (ORM) is used to model the semantics of a universe of discourse. ORM is often used for data modeling and software engineering.

An object-role model uses graphical symbols that are based on first order predicate logic and set theory to enable the modeler to create an unambiguous definition of an arbitrary universe of discourse.

The term "object-role model" was coined in the 1970s and ORM based tools have been used for more than 30 years – principally for data modeling. More recently ORM has been used to model business rules, XML-Schemas, data warehouses, requirements engineering and web forms.

History

The roots of ORM can be traced to research into semantic modeling for information systems in Europe during the 1970s. There were many pioneers and this short summary does not by any means mention them all. An early contribution came in 1973 when Michael Senko wrote about "data structuring" in the IBM Systems Journal. In 1974 Jean-Raymond Abrial contributed an article about "Data Semantics". In June 1975, Eckhard Falkenberg's doctoral thesis was published and in 1976 one of Falkenberg's papers mentions the term "object-role model".

G.M. 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. Robert Meersman extended the approach by adding subtyping, and introducing the first truly conceptual query language.

Object role modeling also evolved from the Natural language Information Analysis Method, a methodology that was initially developed by the academic researcher, G.M. Nijssen in the Netherlands (Europe) in the mid-1970s and his research team at the Control Data Corporation Research Laboratory in Belgium, and later at the University of Queensland, Australia in the 1980s. The acronym NIAM originally stood for "Nijssen's Information Analysis Methodology", and later generalised to "Natural language Information Analysis Methodology" and Binary Relationship Modeling since G. M. Nijssen was only one of many people involved in the development of the method.

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

Also in 1989, Terry Halpin and G.M. Nijssen co-authored the book "Conceptual Schema and Relational Database Design" and several joint papers, providing the first formalization of Object-Role Modeling. Since then Dr. Terry Halpin has authored six books and over 160 technical papers.

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. It was originally named Genesys and was marketed successfully in France and later Canada. It could also handle ER diagram design. It was ported to SCO Unix, SunOs, DEC 3151's and Windows 3.0 platforms, and was later migrated to succeeding Microsoft operating systems, utilising XVT for cross operating system graphical portability. The tool was renamed OORIANE and is currently being used for large data warehouse and SOA projects.

Also evolving from NIAM is "Fully Communication Oriented Information Modeling" FCO-IM (1992). It distinguishes itself from traditional ORM in that it takes a strict communication-oriented perspective. Rather than attempting to model the domain and its essential concepts, it models the communication in this domain (universe of discourse). Another important difference is that it does this on instance level, deriving type level and object/fact level during analysis.

Another recent development is the use of ORM in combination with standardised relation types with associated roles and a standard machine-readable dictionary and taxonomy of concepts as are provided in the Gellish English dictionary. Standardisation of relation types (fact types), roles and concepts enables increased possibilities for model integration and model reuse.

Object-Role Modeling concepts

Overview of the Object-Role Model notation, Stephen M. Richard (1999).

Facts

Object-role models are based on elementary facts, and expressed in diagrams that can be verbalised into natural language. A fact is a proposition such as "John Smith was hired on 5 January 1995" or "Mary Jones was hired on 3 March 2010".

With ORM, propositions such as these, are abstracted into "fact types" for example "Person was hired on Date" and the individual propositions are regarded as sample data. The difference between a "fact" and an "elementary fact" is that an elementary fact cannot be simplified without loss of meaning. This "fact-based" approach facilitates modeling, transforming, and querying information from any domain.

Attribute-free

ORM is attribute-free : unlike Entity Relationship (ER) and Unified Modeling Language (UML) models, 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 in the base model, ORM improves semantic stability and enables verbalization into natural language.

Fact-based modeling

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

Fact-based textual representations are based on formal subsets of native languages. ORM proponents argue that ORM models are easier to understand by people without a technical education. For example, proponents argue that Object-Role Models are easier to understand than declarative languages such as Object Constraint Language (OCL) and other graphical languages such as UML class models. Fact-based graphical notations are more expressive than those of ER and UML. An object-role model can be automatically mapped to relational and deductive databases (such as datalog).

ORM 2 graphical notation

ORM2 is the latest generation of Object-Role Modeling . The main objectives for the ORM 2 graphical notation are:

• More compact display of ORM models without compromising clarity
• Improved internationalization (e.g. avoid English language symbols)
• Simplified drawing rules to facilitate creation of a graphical editor
• Extended use of views for selectively displaying/suppressing detail
• Support for new features (e.g. role path delineation, closure aspects, modalities)

Design procedure

Example of the application of Object Role Modeling in a "Schema for Geologic Surface", Stephen M. Richard (1999).

System development typically involves several stages such as: feasibility study; requirements analysis; conceptual design of data and operations; logical design; external design; prototyping; internal design and implementation; testing and validation; and maintenance. The seven steps of the conceptual schema design procedure are:

1. Transform familiar information examples into elementary facts, and apply quality checks
2. Draw the fact types, and apply a population check
3. Check for entity types that should be combined, and note any arithmetic derivations
4. Add uniqueness constraints, and check arity of fact types
5. Add mandatory role constraints, and check for logical derivations
6. Add value, set comparison and subtyping constraints
7. Add other constraints and perform final checks

ORM's conceptual schema design procedure (CSDP) focuses on the analysis and design of data.

Tools

ORMLite

ORMLite is a free, open-source modeling tool that supports ORM 2 notation. It was created as a self-learning environment to help popularize ORM. It can verbalize facts and generate relational models. It is written in Python and so it is multi-platform. Version 0.13b was released in November 2012. .

NORMA

Dr. Terry Halpin led the initial development of the NORMA ORM modeling tool whilst he was a Professor at Neumont University. This is now supported via The ORM Foundation, a UK-based non-profit organization dedicated to the promotion of the object-role modeling.

NORMA (Natural ORM Architect for Visual Studio) is a free and open source plug-in to Microsoft Visual Studio 2005, Visual Studio 2008, Visual Studio 2010 and Visual Studio 2012. NORMA supports second generation ORM(ORM 2), and can be used to generate code from and object-role model to several implementation targets, such as major database engines, object-oriented code, and XML schema. Examples include:

Database engines	Microsoft Sql Server, Oracle, DB2, MySQL, PostgreSQL, etc.
Programming languages	LINQ to SQL, PLiX (Programming Language in XML) and PHP
Other	XML schemas (XSD)

Advantages of NORMA include:

• Accepts text input and automatically generates graphics
• Validates common constraints and completeness as the model is entered
• Provides simultaneous narrative and graphic versions of all models
• Provides multiple vies of a model(ORM graphics, Relational, E-R and text narrative)
• Automatic navigation from error message to graphic view of the error
• The four views (ORM, Relational, E-R and narrative) provide useful access for modelers. However, the narrative view of the model is easier to read by those who are not familiar with ORM, Relational or E-R diagrams.
• Can reverse-engineer a physical database (partial)
• Narrative view uses hyperlinks for full cross-referencing
• Graphical model has no fixed bounds

Dr. Terry Halpin's 2008 book, Information Modeling and Relational Databases, Second Edition "...uses the notation of ORM 2 (second generation ORM), as supported by the NORMA (Natural ORM Architect) tool..." (page 10), and "(...) At the time of writing, the Natural ORM Architect (NORMA) tool provides the most complete support for the ORM 2 notation discussed in this book." (Preface, xxv).

As of April 2009, the NORMA project delivers frequent releases.

Each new NORMA Community Technical Preview (CTP) is published in the library of The ORM Foundation website.

DogmaModeler

DogmaModeler Screenshot.

DogmaModeler is a free ontology modeling tool based on Object role modeling. The philosophy of DogmaModeler is to enable non-IT experts to model ontologies with a little or no involvement of an ontology engineer.

This challenge is tackled in DogmaModeler through well-defined methodological principles. The first version of DogmaModeler was developed at the Vrije Universiteit Brussel.

DogmaModeler open source status

The DogmaModeler Project shows no activity since its creation in 2006, and the source code for the project is not available through that site. The latest version of the program, available at the http://jarrar.info/Dogmamodeler website is dated on October 27, 2006.

Since then the project seems to have been continued and expanded into several other tools at the Vrije Universiteit Brussel's Semantics Technology and Applications Research Laboratory (VUB STARLab). A note on that site states "Users who only use DOGMAModeler for their own researches can contact (author's email) for the free download."

VisioModeler

The former ORM tool known as VisioModeler is freely available as an unsupported product from Microsoft Corporation (as a 25 MB download). Models developed in VisioModeler may be exported to Microsoft's current and future ORM solutions. To obtain the free VisioModeler download, go to http://download.microsoft.com, search by selecting Keyword Search, enter the keyword "VisioModeler", select your operating system (e.g. Windows XP—Note: VisioModeler does not work under Windows Vista), change the setting for "Show Results for" to "All Downloads", and hit the "Find It!" button. This should bring up a download page that includes the title "VisioModeler (Unsupported Product Edition)". Clicking on this will take you to the link for the download file MSVM31.exe. Click on this to do the download.

The early ORM tools such as IAST (Control Data) and RIDL* were followed by InfoDesigner, InfoModeler and VisioModeler.

When Microsoft bought the Visio Corporation, Microsoft extended VisioModeler and made it a component of Microsoft Visual Studio. This was Microsoft's first ORM implementation and it was published in the 2003 Enterprise Architects release of Visual Studio as a component of the tool called "Microsoft Visio for Enterprise Architects (VEA)".

In the same year, a companion "how to" book was published by Morgan Kaufmann entitled "Database Modeling with Microsoft Visio for Enterprise Architects" . Microsoft has retained the ORM functionality in the high-end version of Visual Studio 2005 and the Morgan Kaufmann book remains a suitable user guide for both versions.

Visio for Enterprise Architects (VEA)

Microsoft included a powerful ORM and logical database modeling solution within its Visio for Enterprise Architects (VEA) product. The 2005 release of VEA also included some minor upgrades (e.g. a driver for SQL Server 2005 was included).

CaseTalk

A modeling tool called CaseTalk based on the ORM-dialect known as Fully Communication Oriented Information Modeling (FCO-IM) is developed and maintained by Oelan in the Netherlands. To find out more about this tool, check the CaseTalk website.

Infagon

A freeware ORM tool known as Infagon is available from Mattic software. Infagon is also based on the FCO-IM dialect. To download or obtain more details about this tool, click the Infagon home page.

Other tools

• Doctool and CogNIAM (CogNIAM tools).
• ActiveFacts (ORM 2 tools),.
• DogmaStudio (ORM Ontology tool),.
• Orthogonal Toolbox (free XML add-on to database modeling COM API for Microsoft's ORM solution).

See also

• Concept map
• Conceptual schema
• Ontology double articulation
• Ontology engineering
• Relational algebra
• Three schema approach

Further reading

• FCO-IM Publications, fco-im.nl
• Terry Halpin (2001), Object-Role Modeling: an overview
• Terry Halpin (2005), ORM2 On the Move to Meaningful Internet Systems 2005: OTM 2005 Workshops, eds R. Meersman, Z. Tari, P. Herrero et al., Cyprus. Springer LNCS 3762, pp 676–87.
• Halpin, Terry (1989), Conceptual Schema and Relational Database Design, Sydney: Prentice Hall, ISBN 978-0-13-167263-5
• Rossi, Matti; Siau, Keng (April 2001), Information Modeling in the New Millennium, IGI Global, ISBN 978-1-878289-77-3
• Halpin, Terry; Evans, Ken; Hallock, Pat; Maclean, Bill (September 2003), Database Modeling with Microsoft Visio for Enterprise Architects, Morgan Kaufmann, ISBN 978-1-55860-919-8
• Halpin, Terry; Morgan, Tony (March 2008), Information Modeling and Relational Databases: From Conceptual Analysis to Logical Design (2nd ed.), Morgan Kaufmann, ISBN 978-0-12-373568-3

External links

• The ORM Foundation
• Terry Halpin's ORM site
• Pieter De Leenheer's blog on fact-based ontology modelling
• PNA Group: Dutch consultancy for fact-based modeling
• Collibra: Information Governance software based on fact-oriented ontologies (using OMG SBVR)
• Erik Proper's publications site
• STARLab group at Free University of Brussels
• NIAM/ORM
• NORMA - Natural Object Role Modeling Architect
• NORMA - The ORM Project at SourceForge
• DOGMA Studio, an Eclipse plugin-based fact-oriented ontology engineering tool suite
• CaseTalk, The FCO-IM casetool
• DogmaModeler, an ontology Engineering tool based on ORM
• ORM Workshops: ORM-2005, ORM-2006, ORM2007, ORM-2008
• ORM 2010 Workshop (held on 27–29 October 2010 in Hersonissou, Crete, Greece)
• The website of the Fact-Based Modeling working group.