Entity Relationship modeling from an ORM perspective: Part 3

This article is the third in a series of articles dealing with Entity Relationship (ER) modeling from the perspective of Object Role Modeling (ORM). Part 1 provided a brief overview of the ER approach, and then covered the basics of the Barker ER notation. Part 2 completed the examination of the Barker ER notation by discussing verbalization, exclusion constraints, frequency constraints, subtyping and nontransferable relationships. Both parts compared the Barker notations with the corresponding ORM notations This article discusses the Information Engineering notation for ER, relating it to relevant ORM constructs. The Information Engineering (IE) approach began with the work of Clive Finkelstein in Australia, and CACI in the UK, and was later adapted by James Martin. Different versions of IE exist, with no single standard. In one form or other, IE is supported by many data modeling tools, and is one of the most popular notations for database design.