Representation term

A representation term is a word, or a combination of words, that semantically represent the data type (value domain) of a data element. A representation term is commonly referred to as a class word by those familiar with data dictionaries. ISO/IEC 11179-5:2005 defines representation term as a designation of an instance of a representation class As used in ISO/IEC 11179, the representation term is that part of a data element name that provides a semantic pointer to the underlying data type. A Representation class is a class of representations. This representation class provides a way to classify or group data elements.

A Representation Term may be thought of as an attribute of a data element in a metadata registry that classifies the data element according to the type of data stored in the data element.

Representation terms are typically "approved" by the organization or standards body using them. For example, the UN publishes its approved list as part of the UN/CEFACT Core Components Technical Specification. The Universal Data Element Framework uses a subset of CCTS representation terms and assigns numeric codes to those used.

A value domain expresses the set of allowed values for a data element. The representation term (and typically the corresponding data type term) comprise a taxonomy for the value domains within a data set. This taxonomy is the representation class. Thus the representation term can be used to control proliferation of value domains by ensuring equivalent value domains use the same representation term.

When a person or software agent is analyzing two separate metadata registries to find property equivalence, the Representation Term can be used as a guide. For example, if system A has a Data Element such as PersonGenderCode and system B has a data element such as PersonSexCode the code suffix might assist the two systems to only match data elements that have the suffix "Code". However, a taxonomy of property terms (i.e. "Sex" or "Gender") is much more efficient in this respect.

The Representation Term can be used in many ways to do inferences on data sets. Representation Terms tells the observer of any data stream about the data types and gives an indication of how the Data Element can be used. This is critical when mapping metadata registries to external Data Elements. For example, if you are sent a record about a person you may look for any "ID" suffix to understand how the remote system may differentiate two distinct records.

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