- October 1, 2019
Most difficult data modeling questions
Read moreAt Data Modeling Zone Europe, I will be teaching a full day Advanced Data Modeling Challenges Workshop. I always love to end these workshops by asking a few difficult data modeling questions that I have been asked over the last 12 months. For example, at last...
10 - August 2, 2019
Captivating name for CDM?
Read moreI am heads down on my next book, which is a book on the power of the conceptual data model. The book is written for business managers and business analysts, and I therefore hesitate to use the term “conceptual data model”. Years ago, I’ve called this...
- March 1, 2019
Can an indicator be NULL?
Read moreAn attribute that is defined as an indicator has only two values, such as Active/Inactive, Yes/No, True/False, and On/Off. I was asked during a training class this week if NULL (empty) can also be a value. Can an indicator attribute have three values, such as Active,...
- February 3, 2019
Ambiguity in Definitions
Read moreI review many data models throughout the year using the Data Model Scorecard technique, and over 95% of the entity and attribute definitions reviewed lack precision. There are certain terms in a definition that, if not explained, automatically make the definition imprecise and vague. The terms...
- January 6, 2019
Is stability an important property for a candidate key on the logical data model?
Read moreA candidate key is an attribute (or set of attributes) that identifies an entity. A candidate key is either a primary key or an alternate key. So for example, in the following Student entity, there are two candidate keys: a primary key on Student Number and...