Representation term
Encyclopedia
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 element
s.
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.
, 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.
(which refer to a Representation Term as a "Property Word") assign unique integer IDs to each Representation Term. This allows metadata mapping tools to map one set of data elements into other metadata vocabularies. An example of these mappings can be found at Property word ID. Note that as of November 2005 the UDEF concepts have not been widely adopted.
123-45-6789
John
Smith
1990-08-14
In the example above, the Representation terms are "ID" for the, the suffix "Name" for the Given and Family names, and "Date" for the .
3.0: [note: the restrictions expressed here are limited to those specifications and do not represent universal consensus]
[Note] This is an extremely limited set of the wide range of standards that specify the use of representation terms.
Data dictionary
A data dictionary, or metadata repository, as defined in the IBM Dictionary of Computing, is a "centralized repository of information about data such as meaning, relationships to other data, origin, usage, and format." The term may have one of several closely related meanings pertaining to...
. ISO/IEC 11179-5:2005 defines representation term as a designation of an instance of a representation class As used 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 :...
, the representation term is that 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...
that provides a semantic pointer to the underlying data type. A Representation class
Representation class
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....
is a class of representations. This 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 Term may be thought of as an attribute of 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...
in a metadata registry
Metadata registry
A metadata registry is a central location in an organization where metadata definitions are stored and maintained in a controlled method.-Use of Metadata Registries:...
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
Universal Data Element Framework
The Universal Data Element Framework provides the foundation for building an enterprise-wide controlled vocabulary. It is a standard way of indexing enterprise information that can produce big cost savings...
uses a subset of CCTS representation terms and assigns numeric codes to those used.
Managing Value Domains
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.Finding equivalent properties
When a person or software agent is analyzing two separate metadata registries to find property equivalenceProperty equivalence
In metadata, property equivalence is the statement that two properties have the same property extension or values. This usually implies that the two properties have the same semantics or meaning...
, 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.
Inference
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.Required fields
Representation Terms are also used to make inferences about the requirements of a property. For example if a data stream had Data Element PersonBirthDateAndTime you would know that BOTH the date AND time are available and relevant, not just the date. If the birth time was optional, a separate data elements should be used such as PersonBirthDate and PersonBirthTime.Finding data warehouse dimensions and measures
When creating a data warehouse, a business analyst looks at the Representation Terms to quickly find the dimensions and measures of a subject matter in order to build OLAP cubes. For example:- Indicator or Code are used to create data warehouse dimensions
- Date or DateTime are used to relate to the time dimension, which are frequently shared between cubes using conformed dimensions
- Amount, Number, Measure or Value terms (which can be added together) are candidates for a measurement
- Name and Text are used for screen labels or other descriptive elements
- Percent needs to be analyzed since they can't really be added together with clear meaning
- ID is used to remove duplicate records
Core Components Technical Specification
The joint ISO/UN Core Components Technical Specification formally define both the allowed set of representation terms and the corresponding set of data types. ISO 15000-5 is an implementation layer of ISO 11179 and normatively expresses a set of rules to semantically define conceptual and physical/logical data models for a wide variety of uses. In ISO 15000-5, the representation term provides a mechanism to harmonize the value domains of candidate data elements before being added to the overall data model(s). ISO 15000-5 is being used by a number of government, standards development organizations, and private sector as the basis for data modeling.Universal Data Element Framework
Some informal standards such as the Universal Data Element FrameworkUniversal Data Element Framework
The Universal Data Element Framework provides the foundation for building an enterprise-wide controlled vocabulary. It is a standard way of indexing enterprise information that can produce big cost savings...
(which refer to a Representation Term as a "Property Word") assign unique integer IDs to each Representation Term. This allows metadata mapping tools to map one set of data elements into other metadata vocabularies. An example of these mappings can be found at Property word ID. Note that as of November 2005 the UDEF concepts have not been widely adopted.
Example of representation terms as an XML suffix
For example if an XML Data fragment had the following:In the example above, the Representation terms are "ID" for the
Sample representation terms
The following are samples of Representation Terms that have been used for the exchange of electronic messages in systems such as NIEM or GJXDMGJXDM
The Global Justice XML Data Model is a data reference model for the exchange of information within the justice and public safety communities...
3.0: [note: the restrictions expressed here are limited to those specifications and do not represent universal consensus]
| Term | Usage |
|---|---|
| Amount | Monetary value with units of currency. |
| BinaryObject BinaryObject (metadata) In metadata a Binary Object is a representation term used to describe a set of finite-length sequences of binary octets used to represent sound, images and other structures.... |
Set of finite-length sequences of binary octets used to represent sound, images and other structures. |
| Code Code (metadata) In metadata, the representation term code refers to, and is used in the name of, data elements whose allowable values can be represented as enumerated lists. Each enumerated value is a string that for brevity represents a specific meaning. For example, for a PersonGenderCode the allowable code... |
An enumerated list of all allowable values. Each enumerated value is a string that for brevity represents a specific meaning. For example for a PersonGenderCode the valid values might be "male", "female" or "unknown". |
| Date Date (metadata) In metadata, the term date is a representation term used to specify a calendar date in the Gregorian calendar. Many data representation standards such as XML, XML Schema, Web Ontology Language specify that ISO date format ISO 8601 should be used.... |
An ISO 8601 ISO 8601 ISO 8601 Data elements and interchange formats – Information interchange – Representation of dates and times is an international standard covering the exchange of date and time-related data. It was issued by the International Organization for Standardization and was first published in 1988... date usually in the format YYYY-MM-DD |
| DateTime | An ISO 8601 ISO 8601 ISO 8601 Data elements and interchange formats – Information interchange – Representation of dates and times is an international standard covering the exchange of date and time-related data. It was issued by the International Organization for Standardization and was first published in 1988... date (in the format YYYY-MM-DD) AND time structure. Note: Do not use unless BOTH the date AND time are REQUIRED fields. If one OR the other is optional always specify the data elements as separate date and time elements. |
| Graphic | Used to store images. Secondary to Binary Object. |
| ID | Abbreviation for Identifier |
| Identifier | A language-independent label, sign or token used to establish identity of, and uniquely distinguish one instance of an object within an identification scheme Identification scheme In metadata, an identification scheme is used to identify unique records in a set.If a data element is used to identify a record within a data set, the data element uses the Identifier representation term.... . |
| Indicator Indicator (metadata) In metadata an indicator is a Boolean value that may contain only the values true or false. The definition of an Indicator must include the meaning of a true value and should also include the meaning if the value is false.... |
Boolean, exactly two mutually exclusive values (true or false). A precise definition must be given for the meaning of a true value. |
| Measure | Numeric value determined by measurement with units. Typically used with items such as height or weight. if the unit of measure is not clear it should be specified. |
| Name | A textual label used as identification of an object. A name is usually meaningful in some language, and is the primary means of identification of objects for humans. Unlike an identifier, a name is not necessarily unique. |
| Number | Assigned or determined by calculation. |
| Text | Character string generally in the form of words. |
| Time Time (metadata) Under some metadata standards, time is a representation term used to specify a time of day in the in ISO 8601 time format.Note that Time should not be confused with the DateAndTime representation term which requires that both the date and time to be supplied.-See also:* metadata* ISO/IEC 11179*... |
An ISO 8601 ISO 8601 ISO 8601 Data elements and interchange formats – Information interchange – Representation of dates and times is an international standard covering the exchange of date and time-related data. It was issued by the International Organization for Standardization and was first published in 1988... time structure. |
| Value | A type of Numeric. |
| Percent | A type of Numeric that traditionally is the results of a ratio calculation that ranges from values of 0 to 1 for values of 0% to 100%. |
| Quantity | Non-monetary numeric value or count with units. |
| Rate | A type of Numeric |
| Year Year (metadata) In metadata, year is a representation term used to specify a year in the Gregorian calendar systems.-Example in XML:If a vehicle has a model year the XML data element may be: 2006... |
An ISO 8601 ISO 8601 ISO 8601 Data elements and interchange formats – Information interchange – Representation of dates and times is an international standard covering the exchange of date and time-related data. It was issued by the International Organization for Standardization and was first published in 1988... Year |
Pros of representation terms
- Use of representation terms in a data element name is a convention that is widely adopted by several large systems such as NIEM, GJXDMGJXDMThe Global Justice XML Data Model is a data reference model for the exchange of information within the justice and public safety communities...
and ebXMLEbXMLElectronic Business using eXtensible Markup Language, commonly known as e-business XML, or ebXML as it is typically referred to, is a family of XML based standards sponsored by OASIS and UN/CEFACT whose mission is to provide an open, XML-based infrastructure that enables the global use of...
. - Many data architects that are responsible for mapping XML from foreign sources find Representation terms very useful.
- Standards such as the UDEF depend on accurate coding of Representation Terms.
- Tools that validate against enumeration lists can distinguish coded values quickly by looking for the "Code" suffix.
- Dimensional analysisDimensional analysisIn physics and all science, dimensional analysis is a tool to find or check relations among physical quantities by using their dimensions. The dimension of a physical quantity is the combination of the basic physical dimensions which describe it; for example, speed has the dimension length per...
of data can use representation terms for creating data warehouses. Representation terms such as Code and Indicator can be converted into dimensions and Amounts and Measures can be converted to measures in a fact table.
Cons of representation terms
- No universal agreement exists as to the definitive set of representation terms.
- There is not always a direct relationship between a representation term and the value domain it represents. This is caused by further qualifying the corresponding data type term.
Standards that use Representation Terms
- Electronic Business using eXtensible Markup LanguageEbXMLElectronic Business using eXtensible Markup Language, commonly known as e-business XML, or ebXML as it is typically referred to, is a family of XML based standards sponsored by OASIS and UN/CEFACT whose mission is to provide an open, XML-based infrastructure that enables the global use of...
- The US Government's National Information Exchange ModelNational Information Exchange ModelThe National Information Exchange Model is an XML-based information exchange framework from the United States. NIEM represents a collaborative partnership of agencies and organizations across all levels of government and with private industry...
requires the use of representation terms for XML data elements. - The US Department of Justice data exchange standards Global Justice XML Data Model required the use of representation terms for XML data elements.
[Note] This is an extremely limited set of the wide range of standards that specify the use of representation terms.
See also
- ISO/IEC 11179ISO/IEC 11179ISO/IEC 11179 is an international standard for representing metadata for an organization in a metadata registry.- Intended purpose :...
- MetadataMetadataThe term metadata is an ambiguous term which is used for two fundamentally different concepts . Although the expression "data about data" is often used, it does not apply to both in the same way. Structural metadata, the design and specification of data structures, cannot be about data, because at...
- Data elementData elementIn 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...
- Representation classRepresentation classA 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....
- Universal Data Element FrameworkUniversal Data Element FrameworkThe Universal Data Element Framework provides the foundation for building an enterprise-wide controlled vocabulary. It is a standard way of indexing enterprise information that can produce big cost savings...
- XMLXMLExtensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....
- XML SchemaXML SchemaXML Schema, published as a W3C recommendation in May 2001, is one of several XML schema languages. It was the first separate schema language for XML to achieve Recommendation status by the W3C...
External links
- ISO/TS 15000-5:2005 Electronic Business Extensible Markup Language (ebXML) -- Part 5: ebXML Core Components Technical Specification, Version 2.01(ebCCTS) (1MB pdf file)
- ISO/IEC 11179-3:2003 Metadata registries (MDR) — Part 3: Registry metamodel & basic attributes (546K zip file)
- ISO/IEC 11179-5:2005 Metadata registries (MDR) — Part 5: Naming and identification principles (238K zip file)
- ISO/IEC TR 11404:1996 Language-independent datatypes (14 MB zip file)
- ISO/IEC TR 20943-1:2003(E) Procedures for Achieving Metadata Registry Content Consistency — Part 1: Data elements See page 84.(700K zip file)
- DOJ and GJXDM training slides on naming
- ISO/IEC JTC 1/SC 32/WG 2 Metadata
- US Department of Interior represnation terms