Representation class
Encyclopedia
A representation term
is a word, or a combination of words, used as part of a data element name
. Representation class is sometimes used as a synonym
for representation term.
In ISO/IEC 11179
, a representation class provides a way to classify or group data element
s. A representation class is effectively a specialized classification scheme
. Hence, there is currently some discussion in ISO over the merits of keeping representation class as a separate entity in 11179, versus collapsing it into the general classification scheme facility. A clear distinction between the two mechanisms, however, is that 11179 allows a data element to be classified by only one representation class, whereas there is no such restriction on other classification schemes.
ISO/IEC 11179 does not specify that representation terms should be drawn from the values of representation class, though it would make sense to do so, nor does it provide any mechanism to ensure any sort of consistency (whatever that might mean) between the representation terms used to name a data element, and the representation class used to classify it.
The term representation class has been used in metadata registry standards for many years. Today it has a combination of meanings and now goes well beyond how a data element
is represented in a computer system. In practice this term is used to shed light on the semantics
or meaning of the data element.
Representation class is the value domain for representation. The set of classes make it easy to distinguish among the elements in the registry. For instance, a data element categorized with the representation class amount is different from an element categorized as number. It probably will not make sense to compare the contents of these elements, or perform calculations using them together.
Representation class is a mechanism by which the functional and/or presentational category of an item may be conveyed to the user.
the class of representation of a data element
Representation term
A representation term is a word, or a combination of words, that semantically represent the data type of a data element. A representation term is commonly referred to as a class word by those familiar with data dictionaries...
is a word, or a combination of words, used as part of a data element name
Data element name
A data element name is a name given to a data element in, for example, a data dictionary or metadata registry. In a formal data dictionary, there is often a requirement that no two data elements may have the same name, to allow the data element name to become an identifier, though some data...
. Representation class is sometimes used as a synonym
Synonym
Synonyms are different words with almost identical or similar meanings. Words that are synonyms are said to be synonymous, and the state of being a synonym is called synonymy. The word comes from Ancient Greek syn and onoma . The words car and automobile are synonyms...
for representation term.
In ISO/IEC 11179
ISO/IEC 11179
ISO/IEC 11179 is an international standard for representing metadata for an organization in a metadata registry.- Intended purpose :...
, a representation class provides a way to classify or group data element
Data element
In metadata, the term data element is an atomic unit of data that has precise meaning or precise semantics. A data element has:# An identification such as a data element name# A clear data element definition# One or more representation terms...
s. A representation class is effectively a specialized classification scheme
Classification scheme
In metadata a classification scheme is a hierarchical arrangement of kinds of things or groups of kinds of things. Typically it is accompanied by descriptive information of the classes or groups. A classification scheme is intended to be used for an arrangement or division of individual objects...
. Hence, there is currently some discussion in ISO over the merits of keeping representation class as a separate entity in 11179, versus collapsing it into the general classification scheme facility. A clear distinction between the two mechanisms, however, is that 11179 allows a data element to be classified by only one representation class, whereas there is no such restriction on other classification schemes.
ISO/IEC 11179 does not specify that representation terms should be drawn from the values of representation class, though it would make sense to do so, nor does it provide any mechanism to ensure any sort of consistency (whatever that might mean) between the representation terms used to name a data element, and the representation class used to classify it.
The term representation class has been used in metadata registry standards for many years. Today it has a combination of meanings and now goes well beyond how a data element
Data element
In metadata, the term data element is an atomic unit of data that has precise meaning or precise semantics. A data element has:# An identification such as a data element name# A clear data element definition# One or more representation terms...
is represented in a computer system. In practice this term is used to shed light on the semantics
Semantics
Semantics is the study of meaning. It focuses on the relation between signifiers, such as words, phrases, signs and symbols, and what they stand for, their denotata....
or meaning of the data element.
Definitions of "representation class"
There are several alternate definitions for representation class. Some of these are taken from the ISO documents. Note that these documents are copyrighted and extracts can only be taken under the fair use rules.From ISO/IEC TR 20943-1 First edition 2003-08-01 pdf page 91
B.2.3 Representation classRepresentation class is the value domain for representation. The set of classes make it easy to distinguish among the elements in the registry. For instance, a data element categorized with the representation class amount is different from an element categorized as number. It probably will not make sense to compare the contents of these elements, or perform calculations using them together.
Representation class is a mechanism by which the functional and/or presentational category of an item may be conveyed to the user.
From ISO/IEC 11179-3 Second edition 2003-02-15
3.3.51 data element representation classthe class of representation of a data element
External links
- ISO/IEC TR 20943-1:2003(E) Procedures for Achieving Metadata Registry Content Consistency — Part 1: Data elements
(page 84) (700K zip file) - ISO/IEC 11179-1 Metadata registries (MDR) — Part 1: Framework (233K zip file)
- ISO/IEC 11179-3 Metadata registries (MDR) — Part 3: Registry metamodel and basic attributes (546K zip file)
- ISO/IEC 11179-5 Metadata registries (MDR) — Part 5: Naming and identification principles (238K zip file)
- DOJ and GJXDM training slides on naming