Characteristic - Characteristic (internal data type)

A characteristic is a property that refers to an elementary type (number, text date, time etc.) or classification. Characteristics may refer to single or multiple elements (e.g. given names ). Supersets for attributes might be defined as value domains, which may refer to another property or to a classification.

Characteristics can be divided into several subcategories depending on the purpose of the characteristic:

• Identifying characteristic - are used for identifying instances of an object type in an object collection
• Classifying characteristic - allow classifying an object instance according to the classification or superset the characteristic is based on
• Quantifying characteristic - provide quantities as object characteristic
• Aggregation characteristic - contains aggregated data for an aggregation type
• Descriptive characteristic - provides textual information for an individual object

The concept of characteristics restricts characteristic instances to elementary values. Data modeling also supports complex attributes [ODMG], which are conceptually considered as parts. The way of implementing complex attributes is, however, not of interest for the terminology model.

When a characteristic refers to a classification as type, the classification defines the value domain (set of permissible values) for the characteristic.