Object–role modeling: Difference between revisions

Revision as of 03:25, 4 October 2020

Revision as of 21:23, 13 January 2021

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[[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.<ref>{{cite book |last=Wintraecken |first=J. J. V. R. |date=1990 |origyearorig-year=1987 |title=The NIAM information analysis method: theory and practice |series=Translation of: Informatie-analyse volgens NIAM |___location=Dordrecht; Boston |publisher=[[Kluwer Academic Publishers]] |isbn=079230263X |oclc=19554537 |doi=10.1007/978-94-009-0451-4 |s2cid=30209824 |url=https://books.google.com/books?id=iJaqCAAAQBAJ}}</ref>

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

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[[Fact-based modelling]] includes procedures for mapping facts to attribute-based structures, such as those of ER or UML.<ref name="orm.net"/>

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 [[Unified Modeling Language|UML]] class models.<ref name="orm.net"/> Fact-based graphical notations are more expressive than those of ER and [[Unified Modeling Language|UML]]. An object-role model can be automatically mapped to relational and deductive databases (such as [[datalog]]).<ref>{{Cite web|url=http://www.ormfoundation.org/files/folders/orm_2010/entry2360.aspx|title=P:11 Mapping ORM To Datalog - an Overview - The ORM Foundation|website=www.ormfoundation.org|accessdateaccess-date=May 31, 2020}}</ref>

=== ORM 2 graphical notation ===

ORM2 is the latest generation of object-role modeling . The main objectives for the ORM 2 graphical notation are:<ref>{{cite web|url=http://www.orm.net/pdf/ORM2.pdf |title=ORM 2 |accessdateaccess-date=April 22, 2009 |url-status=dead |archiveurlarchive-url=https://web.archive.org/web/20090219122007/http://orm.net/pdf/ORM2.pdf |archivedatearchive-date=February 19, 2009 }} Halpin, T. 2005, 'ORM 2', 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.</ref>

* More compact display of ORM models without compromising clarity

* Improved internationalization (e.g. avoid English language symbols)

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| last = Halpin | first = Terry

| author-link = Terry Halpin

| author2-link = G.M. Nijssen

| title = Conceptual Schema and Relational Database Design

| publisher = [[Prentice Hall]]