Month Year

June 1999

Issue: 9

Editor's Notes: Interactive JCM
by Scot A. Becker

UML Data Models from an ORM Perspective (Part 9)
by Dr. Terry Halpin

This paper is the ninth 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 examines initial values and derived data in ORM and UML.

Data Schema Normalization
by Scot A. Becker

The purpose of this white paper is to outline the various normal forms used in ("manual") data schema normalization. This paper begins with a discussion as to why a database designer is concerned with normalization. Immediately following is a discussion of functional dependencies and an introduction to the eight normal forms. This paper is closed with a discussion as to how normalization fits in with the data modeling technique, Object-Role Modeling (ORM).

Mapping Conceptual Names to Logical Names in VisioModeler
by Pat Hallock

The issue of mapping conceptual naming to logical or physical names has presented itself several times in the last few weeks. Therefore, this is a response to that issue as well as requests for more "how-to" type articles. The most influential reason for this article came during a DAMA meeting where a presenter noted that conceptual names were very important, but did not offer a solution for the mapping of conceptual names to the logical level. There are several options for controlling the naming between the conceptual and logical names in VisioModeler in support of Object Role Modeling (ORM).

Dr. John K. Sharp
Everything You Ever Wanted to Know About "City"

Several JCM discussions have brought up issues dealing with the precision and clarity of modeling using ORM/NIAM/NLM. Most of these have centered on the need to assist others in understanding the value of mode precise modeling. This is a continuing challenge for most of us. Information Modeling has been treated as a way to describe the high level or general requirements. Any approach that requires or even allows for a more detailed and precise definition of requirements is suspect due to the general low-value that is associated with design as contrasted to the high value that is associated with coding.

Analysis Problem
Solution for Last Issue's Analysis Problem