Month Year

June 1998

Issue: 3

Editor's Notes: UML: Put out or shut up
by Scot A. Becker

UML Data Models from an ORM Perspective (Part 3)
by Dr. Terry Halpin

This paper is the third in a series of articles examining data modeling in the Unified Modeling Language (UML) from the perspective of Object Role Modeling (ORM). Part 1 provided some historical background on both approaches, identified design criteria for modeling languages, and discussed how object reference and single-valued attributes are modeled in both. Part 2 compared UML multi-valued attributes with ORM relationship types, and discussed basic constraints on both, as well as instantiation using UML object diagrams or ORM fact tables. This third issue compares UML associations and related multiplicity constraints with ORM relationship types and related uniqueness, mandatory role and frequency constraints. It also contrasts instantiation of associations using UML object diagrams and ORM fact tables.

Dealing with Embedded Objects
by Pat Hallock

Modeling projects often have the problem of embedded objects. Embedded objects are those fields that have many sub-parts. The simple example is the field that contains two or more codes that are easily parsed.

InfoModeler Tips and Tricks: General Tips, Issue Three
Dr. Anthony Bloesch

De-normalized for Speed
by Dr. John K. Sharp

How many times have you heard someone say that this application has been de-normalized for speed? This comment usually comes in the mist of a review of the project and is supposed to make the analyst feel better when someone (usually a good NIAM/ORM/NLM modeler) points out errors in the model. In my one experience of a "de-normalized for speed" model tested against the fully normalized model, the normalized model was faster for critical transactions. This may not be a standard outcome, but I am concerned that the "de-normalized for speed" comment may be given when the analyst has no idea about what the "normalized" system would look like.

Analysis Problem
By Dr. Gordon C. Everest

Here is a problem which I gave my students on the mid-term exam in my Advanced Database Design class this spring, at the Carlson School of Management, University of Minnesota. I thought it might be a good one to put in the JCM.

Dr. John K. Sharp
Analysis Problem
Solution for Last Issue's Analysis Problem