Q: Why did you decide recently to write your new book on ORM?
A: Last October, I gave a tutorial on Objet-Role Modeling (ORM) at the Data Modeling Zone conference in Portland, Oregon. This was well received, and Steve Hoberman, who was the conference organizer, invited me to write some practitioner-oriented books on ORM for publication by his company Technics Publications.
Q: What was the motivation behind this new book?
A: In 2008, Tony Morgan and I wrote the second edition of Information Modeling and Relational Databases. In just under 1000 pages this covers a wide range of topics including ORM, ER, UML, relational database theory, SQL, business process modeling, and other content relevant to a university course in information systems. Many database practitioners are already familiar with relational databases and modeling approaches such as ER and UML, but comparatively few are familiar with ORM. For this audience, I felt that a shorter book focused specifically on ORM and written with a minimum of technical language might provide a more approachable resource to help them gain expertise with fact-based modeling.
Q: What’s new and different in this book?
A: In easy-to-understand language, the book covers the latest version of ORM’s conceptual schema design procedure, including recent additions such as strongly intransitive ring constraints. Each step in the design procedure is illustrated with new examples, and each chapter ends with a practical lab that discusses how to use the freeware NORMA tool to enter ORM models, automatically verbalize them, and map them to a relational database. The NORMA tool works as a plug-in to Microsoft Visual Studio, including its Community Edition which is freely available to most users.
Q: It seems from the title, “Object-Role Modeling Fundamentals”, that this sounds like the ‘first’ book on ORM, but it’s at least your third. It’s been nearly 30 years since you wrote your seminal PhD thesis on ORM…does it feel that now ‘the time is right’ for a book dedicated specifically to ORM? It’s almost as if it cements the institutionalisation of an idea…ORM. What are your thoughts on that?
A: Owing to continual refinements resulting from both theoretical research and industrial data modeling experience, ORM has now reached a level of maturity that I believe the time is ripe for wider adoption of ORM in the data modeling community. The advantages of ORM over other data modeling approaches stem from its fact-based approach which expresses the information requirements of any business domain simply in terms of objects that play roles in relationships. All facts of interest are treated as instances of attribute-free structures known as fact types, where the relationship may be unary (e.g. Person smokes), binary (e.g. Person was born on Date), ternary (e.g. Customer bought Product on Date), or longer. Fact types facilitate natural expression, are easy to populate with examples for validation purposes, and have greater semantic stability than attribute-based structures such as those used in ER or UML. All relevant facts, constraints and derivation rules are expressed in controlled natural language sentences that are intelligible to users in the business domain being modeled. This allows ORM data models to be validated by business domain experts who are unfamiliar with ORM’s graphical notation. For the data modeler, ORM’s graphical notation covers a much wider range of constraints than can be expressed in industrial ER or UML class diagrams, and thus allows rich visualization of the underlying semantics.
Q: Where is your new book available?
A: The book is available in both print and electronic form from various channels, such as Amazon, as well as directly from the Technics Publications website. Anyone who orders the print version of the book from the publisher’s website can receive a 25% discount by using the coupon code ORMFundamentals.