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A metadata registry is a central location in an organization where metadata definitions are stored and maintained in a controlled method.
A metadata repository is the database where metadata is stored. The registry also adds relationships with related metadata types. A metadata engine collects, stores and analyzes information about data and metadata (data about data) in use within a domain. [1]
Metadata registries are used whenever data must be used consistently within an organization or group of organizations. Examples of these situations include:
Central to the charter of any metadata management programme is the process of creating trusting relationships with stakeholders and that definitions and structures have been reviewed and approved by appropriate parties.
A metadata registry typically has the following characteristics:
Because metadata registries are used to store both semantics (the meaning of a data element) and systems-specific constraints (for example the maximum length of a string) it is important to identify what systems impose these constraints and to document them. For example the maximum length of a string should not change the meaning of a data element.
The International Organization for Standardization (ISO) has published standards for a metadata registry called ISO/IEC 11179 and also ISO15000-3 and ISO15000-4 ebXML registry and repository (regrep) EbXML RegRep
There are two international standards which are commonly referred to as metadata registry standards: ISO/IEC 11179 and ISO 15000-3. There are some who believe that ISO/IEC 11179 and ISO 15000-3 are interchangeable or at least in some way similar. e.g.
"Of interest is that the ISO 11179 model was one of the inputs to the ebXML RIM (registry information model) and so has much functional equivalence to the "registry" region of the ISO 11179 conceptual model."
This is however incorrect. Although the specification ebRIM v2.0 (5 December 2001) says at the beginning in its Design Objectives: "Leverage as much as possible the work done in the OASIS [OAS] and the ISO 11179 [ISO] Registry models" by the time of ebRIM v3.0 (2 May 2005) all reference to ISO/IOEC 11179 is reduced to a mention under informative references on page 76 of 78. It was recognised by some team members that the ebXML RIM data model had no place to store "fine grained artifacts" ie. the data elements which are at the heart of ISO/IEC 11179, but not until 2009 can an explicit and definitive statement from the team be found.
ISO/IEC 11179 says that it is concerned with "traditional" metadata: "We limit the scope of the term as it is used here in ISO/IEC 11179 to descriptions of data - the more traditional use of the term." Originally the standard named itself a "data element" registry. It describes data elements: "data elements are the fundamental units of data" and "data elements themselves contain various kinds of data that include characters, images, sound, etc." It also describes a registry with an analogy: "This is analogous to the registries maintained by governments to keep track of motor vehicles. A description of each motor vehicle is entered in the registry, but not the vehicle itself."
The ebXML RIM says about its Repository and Registry that it is
It also says that it is
It also describes itself with "...this familiar metaphor. An ebXML Registry is like your local library. The repository is like the bookshelves in the library. The repository items in the repository are like book (sic) on the bookshelves." It goes on to say "The registry is like the card catalog … A RegistryObject is like a card in the card catalog."
What should be immediately apparent is that something which holds catalogue cards is not "like" a catalogue, it IS a catalogue.
Unfortunately for a number of organisations that have implemented ebXML RIM to satisfy a requirement for an ISO/IEC 11179 registry, ebXML RIM
It is
A metadata registry is frequently set up and administered by an organization's data architect or data modeling team.
Data elements are frequently assigned to data stewards or data stewardship teams that are responsible for the maintenance of individual data elements through a secure system.
Metadata registries frequently have a formal data element submission, approval and publishing approval process. Each data element should be accepted by a data stewardship team and reviewed before data elements are published. After publication change control processes should be used.
Metadata registries are frequently large and complex structures and require navigation, visualization and searching tools. Use of hierarchical viewing tools are frequently an essential part of a metadata registry system. Metadata publishing consists of making data element definitions and structures available to both people and other systems.
In alphabetical order:
In alphabetical order:
The Dublin Core, also known as the Dublin Core Metadata Element Set (DCMES), is a set of fifteen main metadata items for describing digital or physical resources. The Dublin Core Metadata Initiative (DCMI) is responsible for formulating the Dublin Core; DCMI is a project of the Association for Information Science and Technology (ASIS&T), a non-profit organization.
In metadata, the term data element is an atomic unit of data that has precise meaning or precise semantics. A data element has:
The Global Justice XML Data Model is a data reference model for the exchange of information within the justice and public safety communities. The Global JXDM is a product of the Global Justice Information Sharing Initiative's (Global) Infrastructure and Standards Working Group (ISWG), and was developed by the Global ISWG's XML Structure Task Force (XSTF).
The ISO/IEC 11179 metadata registry (MDR) standard is an international ISO/IEC standard for representing metadata for an organization in a metadata registry. It documents the standardization and registration of metadata to make data understandable and shareable.
NIEMOpen, frequently referred to as NIEM, originated as an XML-based information exchange framework from the United States, but has transitioned to an OASISOpen Project. This initiative formalizes NIEM's designation as an official standard in national and international policy and procurement. NIEMOpen's Project Governing Board recently approved the first standard under this new project; the Conformance Targets Attribute Specification (CTAS) Version 3.0. A full collection of NIEMOpen standards are anticipated by end of year 2024.
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. 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 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 dictionaries may provide ways to qualify the name in some way, for example by the application system or other context in which it occurs.
In metadata, a data element definition is a human readable phrase or sentence associated with a data element within a data dictionary that describes the meaning or semantics of a data element.
Semantic translation is the process of using semantic information to aid in the translation of data in one representation or data model to another representation or data model. Semantic translation takes advantage of semantics that associate meaning with individual data elements in one dictionary to create an equivalent meaning in a second system.
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.
Metadata publishing is the process of making metadata data elements available to external users, both people and machines using a formal review process and a commitment to change control processes.
The Extended Metadata Registry (XMDR) is a project proposing and testing a set of extensions to the ISO/IEC 11179 metadata registry specifications that deal with the development of improved standards and technology for storing and retrieving the semantics of data elements, terminologies, and concept structures in metadata registries.
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.
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.
Under some metadata standards, time is a representation term used to specify a time of day in the ISO 8601 time format.
The AgMES initiative was developed by the Food and Agriculture Organization (FAO) of the United Nations and aims to encompass issues of semantic standards in the domain of agriculture with respect to description, resource discovery, interoperability, and data exchange for different types of information resources.
Metadata is "data that provides information about other data", but not the content of the data itself, such as the text of a message or the image itself. There are many distinct types of metadata, including:
A metadata standard is a requirement which is intended to establish a common understanding of the meaning or semantics of the data, to ensure correct and proper use and interpretation of the data by its owners and users. To achieve this common understanding, a number of characteristics, or attributes of the data have to be defined, also known as metadata.
Electronic 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 electronic business information in an interoperable, secure, and consistent manner by all trading partners.
In computing, a data definition specification (DDS) is a guideline to ensure comprehensive and consistent data definition. It represents the attributes required to quantify data definition. A comprehensive data definition specification encompasses enterprise data, the hierarchy of data management, prescribed guidance enforcement and criteria to determine compliance.
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Open Forums on Metadata Registries, in reverse chronological order: