Intended purpose 
Today, organizations often want to exchange data quickly and precisely between computer systems using enterprise application integration technologies. Completed transactions are also often transferred to separate data warehouse and business rules systems with structures designed to support data for analysis. The industry de facto standard model for data integration platforms is the Common Warehouse Metamodel (CWM). Data integration is often also solved as a data, rather than a metadata, problem, with the use of so called master data. ISO/IEC 11179 claims that it is a standard for metadata-driven exchange of data in an heterogeneous environment, based on exact definitions of data.
Structure of an ISO/IEC 11179 metadata registry 
The ISO/IEC 11179 model is a result of two principles of semantic theory, combined with basic principles of data modelling.
The first principle from semantic theory is the thesaurus type relation between wider and more narrow (or specific) concepts, i.e. the wide concept "income" has a relation to the more narrow concept "net income".
The second principle from semantic theory is the relation between a concept and its representation, i.e. "buy" and "purchase" are the same concept even if different terms are used.
The basic principle of data modelling is the combination of an object class and a characteristic. For example, "Person - hair color".
When applied to data modelling, ISO/IEC 11179 combines a wide "concept" with an "object class" to form a more specific "data element concept". For example, the high-level concept "income" is combined with the object class "person" to form the data element concept "net income of person". Note that "net income" is more specific than "income".
The different possible representations of a data element concept are then described with the use of one or more data elements. Differences in representation may be a result of the use of synonyms or different value domains in different data sets in a data holding. A value domain is the permitted range of values for a characteristic of an object class. An example of a value domain for "sex of person" is "M = Male, F = Female, U = Unknown". The letters M, F and U are then the permitted values of sex of person in a particular data set.
The data element concept "monthly net income of person" may thus have one data element called "monthly net income of individual by 100 dollar groupings" and one called "monthly net income of person range 0-1000 dollars", etc., depending on the heterogeneity of representation that exists within the data holdings covered by one ISO/IEC 11179 registry. Note that these two examples have different terms for the object class (person/individual) and different value sets (a 0-1000 dollar range as opposed to 100 dollar groupings).
The result of this is a catalogue of sorts, in which related data element concepts are grouped by a high-level concept and an object class, and data elements grouped by a shared data element concept. Strictly speaking, this is not a hierarchy, even if it resembles one.
It is worth noting that ISO/IEC 11179 proper does not describe data as it is actually stored. There is no part of the model that caters to the description of physical files, tables and columns. All the ISO/IEC 11179 constructs are "semantic" as opposed to "physical" or "technical".
Since the standard has two main purposes (definition and exchange) the core object is the data element concept, since it defines a concept and, ideally, describes data independent of its representation in any one system, table, column or organisation.
Structure of the ISO/IEC 11179 standard 
The standard consists of six parts:
- Part 1 - Framework
- Part 2 - Classification
- Part 3 - Registry metamodel and basic attributes
- Part 4 - Formulation of data definitions
- Part 5 - Naming and identification principles
- Part 6 - Registration
Part 1 explains the purpose of each part. Part 3 specifies the metamodel that defines the registry. The other parts specify various aspects of the use of the registry.
Overview of 11179 Data Element 
The data element is foundational concept in an ISO/IEC 11179 metadata registry. The purpose of the registry is to maintain a semantically precise structure of data elements.
Each Data element in an ISO/IEC 11179 metadata registry:
- should be registered according to the Registration guidelines (11179-6)
- will be uniquely identified within the register (11179-5)
- should be named according to Naming and Identification Principles (11179-5) See data element name
- should be defined by the Formulation of Data Definitions rules (11179-4) See data element definition and
- may be classified in a Classification Scheme (11179-2) See classification scheme
Data elements that store "Codes" or enumerated values must also specify the semantics of each of the code values with precise definitions.
Adoption of 11179 Standards 
Despite the rising demand for efficient data integration solutions, Oracle, a major commercial supporter of ISO/IEC 11179 has canceled its support for this standard (see below). However, Software AG's COTS Metadata Registry (MDR) product supports the ISO 11179 standard and continues to be sold and used for this purpose in both commercial and government applications (see Vendor Tools section below).
While commercial adoption is increasing, the spread of ISO/IEC 11179 has been more successful in the public sector. However, it is unclear if this is due to different requirements for data exchange in the public sector, since its spread seems to follow the sphere of influence of the participants in the development of the standard, i.e. the reception is with U.S. government agencies, and with a limited group of national and international statistical organisations.
Organizations such as the United Nations and the US Government are large users of 11179 standards.
11179 is strongly recommended on the U.S. government's XML website. US Government's XML web site and is promoted by The OPEN Group as a foundation of the Universal Data Element Framework (UDEF http://www.opengroup.org/udef/). The Open Group is a vendor-neutral and technology-neutral consortium working to enable access to integrated information within and between enterprises based on open standards and global interoperability.
Extensions to the ISO/IEC 11179 standard 
Although the ISO/IEC 11179 metadata registry is a complex standard comprising several hundreds of pages, there are users that are attempting to extend these standards to meet various challenges. For example the XMDR project states its purpose as being: ...concerned with the development of improved standards and technology for storing and retrieving the semantics of data elements, terminologies, and concept structures in metadata registries. It is, however, uncertain as to how active this effort is at present: the XMDR website () does not list project meetings after October 2007, and also whether it has been able to influence ISO to enhance its standard.
Examples of ISO/IEC 11179 metadata registries 
The following metadata registries state that they follow ISO/IEC 11179 guidelines although there have been no formal third party tests developed to test for metadata registry compliance.
- Australian Institute of Health and Welfare - Metadata Online Registry (METeOR)
- US Department of Justice - Global Justice XML Data Model GJXDM
- US Environmental Protection Agency - Environmental Data Registry
- US Health Information Knowledgebase (USHIK)
- US National Cancer Institute - Cancer Data Standards Repository (caDSR)
- Ohio State University - open Metadata Repository (openMDR)
- US National Information Exchange Model NIEM
- Minnesota Department of Education Metadata Registry (K-12 Data)
- Minnesota Department of Revenue Property Taxation (Real Estate Transactions)
Metadata registry vendor tools that claim ISO/IEC 11179 compliance 
- Software AG's OneData Metadata Registry
- Oracle used to offer Enterprise Metadata Manager (EMM) through their consulting practice but the service is no longer listed on the company web site.
Note that there are no independent agencies that certify ISO/IEC 11179 compliance.
See also 
- Data dictionary
- Data reference model
- Global Justice XML Data Model
- National Information Exchange Model
- Representation term
- Semantic Web
- Universal Data Element Framework
- Metadata standards
- ISO/IEC Joint Technical Committee on Metadata Standards Web Site
- 11179 Document List
- ISO/IEC 11179-1:2004 Metadata registries (MDR) - Part 1: Framework
- ISO/IEC 11179-2:2005 Metadata registries (MDR) - Part 2: Classification
- ISO/IEC 11179-3:2003 Metadata registries (MDR) - Part 3: Registry metamodel and basic attributes
- ISO/IEC 11179-4:2004 Metadata registries (MDR) - Part 4: Formulation of data definitions
- ISO/IEC 11179-5:2005 Metadata registries (MDR) - Part 5: Naming and identification principles
- ISO/IEC 11179-6:2005 Metadata registries (MDR) - Part 6: Registration
- Extended Business XML Naming Conventions
- A (non-normative, unofficial) OWL ontology for ISO/IEC 11179-3 version 2. Authored by Kevin D. Keck (firstname.lastname@example.org). Last modified 2005-Jan-21