Month Year

August 1999

Issue: 10

Editor's Notes: Nothing Much to Say
by Scot A. Becker

UML Data Models from an ORM Perspective (Part 10)
by Dr. Terry Halpin

This paper is the tenth in a series of articles examining data modeling in the Unified Modeling Language (UML) from the perspective of Object Role Modeling (ORM). Part 1 discussed historical background, language design criteria, object reference and single-valued attributes. Part 2 covered multi-valued attributes, basic constraints, and instantiation using UML object diagrams or ORM fact tables. Part 3 compared UML associations and related multiplicity constraints with ORM relationship types and related uniqueness, mandatory role and frequency constraints, as well as how associations may be instantiated. Part 4 contrasted ORM nesting, co-referencing and exclusion constraints with UML association classes, qualified associations, and xor-constraints respectively. Part 5 discussed subset and equality constraints. Part 6 discussed subtyping. Part 7 discussed value, ring and join constraints. Part 8 listed some recent updates to the UML standard, then discussed aggregation. Part 9 examined initial values and derived data in ORM and UML. Part 10 discusses changeability and collection types UML and ORM.

An Argument for the Use of ER Modeling
by Scot A. Becker

The other day I was doing a bunch of repetitive tasks in an Entity-Relationship (ER) model -- this time, I'll be nice and not mention the (shoddy) tool I was using, but I will say that this is the only time in recent memory where I haven't trashed Designer. You can probably guess what I was doing: making sure multiple instances of the same attribute had the same physical name, checking name consistency, checking datatype and domain consistency, putting in audit columns on each table, tapping the space bar to the beat of Carl Weathersby, etc.

Baloney Detection Kit
by Dick Barden

n 1996 Carl Sagan wrote a book titled The Demon-Haunted World: Science as a Candle in the Dark. One of the chapters is titled The Fine Art of Baloney Detection. In it Sagan outlines a checklist for skeptical thinking. Sagan's checklist is used to examine ideas and provide a checklist of activities and advice to assist us in understanding a line of reasoning to determine if it seems plausible or if it just simply falls apart. From the perspective of Object-Role Modeling, this article considers each tool in the kit.

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