# Logical Data Modeling - Classifier (Label, Class, Tag) - Descriptif Attribute

A label is an attribute that describes its entity or relationship with nominal data.

A label is also known as:

• a tag
• a class
• or just a nominal attribute
• a classifier
• a group
• a category

Classifiers / Label can be organized in hierarchies.

They are the output of a classification process

In dimensional data, they are known as dimensional attribute.

## Usage

They are used to label, filter and/or group on whereas additive numeric attribute are used to aggregate over.

They also create an aggregation relationship between entities.

## Identifier

There is two kind of label identifier:

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