# Logical Data Modeling - Classification (Taxonomy | Categorization) - Transversal Data Organization

Classification is an naming technique for organization where entity or relationship gets classified by giving them a nominal attribute known as a classifier.

The classification of organisms in an ordered system that indicates natural relationships; The science, laws, or principles of classification; systematics; Division into ordered groups or categories.

The American Heritage Dictionary of the English Language. Fourth Edition. Boston, MA: Houghton Mifflin Company, 2006.

The output of classification process is an aggregate binary relationship (ie is part of relationship).

In dimensional data, you will find this attributes in dimension.

## Design rule

The magical number may be applied to limit:

• the number of member in a class
• the number of class that classify an entity or a association

### Number of Class member

According to magical number, the number of value that can be choose for every class attribute should be in the range $7 \pm 2$

Example of bad class for a department

• Development
• Computer Science
• Data Services
• Digital Media Innovation Program
• Events Center
• Engineering
• Infrastructure
• Enterprise System Integration
• Project Management

If this is the case, you should create a new level in your package (hierarchy)

### Number of Class

According to magical number, the number of value that define a association or an entity should be in the range $7 \pm 2$

For instance, a fact table should not have more than $7 \pm 2$ dimension.

## Algorithm

Classification can be performed during data processing operations