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

Metadata registries are used whenever data must be used consistently within an organization or group of organizations. Examples of these situations include:

1. Organizations that transmit data using structures such as XML, Web Services or EDI
2. Organizations that need consistent definitions of data across time, between organizations or between processes, for example when an organization builds a data warehouse
3. Organizations that are attempting to break down "silos" of information captured within applications or proprietary file formats

Central to the charter of any metadata management project is the process of creating trusting relationships with stakeholders and that definitions and structures have been reviewed and approved by appropriate parties.

Common characteristics of a metadata registry

A metadata registry typically has the following characteristics:

1. It is a protected area where only approved individuals may make changes
2. It stores data elements that include both semantics and representations
3. The semantic areas of a metadata registry contain the meaning of a data element with precise definitions
4. The representational areas of a metadata registry define how the data is represented in a specific format such as within a database or a structured file format such as XML

Clear separation of semantics and system-specific constraints

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

Metadata registry roles

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.

Metadata element workflow

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 navigation, search and publishing

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 computer systems.

Examples of public metadata registries

• Apelon Medical Registry http://sage.wherever.org/deployment/deployment.html
• Australian Institute of Health and Welfare http://meteor.aihw.gov.au/content/index.phtml/itemId/181162
• Dublin Core Metadata Registry http://dublincore.org/dcregistry/
• Cancer Data Standards Repository http://ncicb.nci.nih.gov/NCICB/infrastructure/cacore_overview/cadsr
• Global Justice XML Data Model (GJXDM) http://www.it.ojp.gov/jxdm/
• Minnesota Department of Education Metadata Registry (K-12 Data)http://education.state.mn.us/mde-dd
• Minnesota Department of Revenue Property Taxation (Real Estate Transactions) http://proptax.mdor.state.mn.us/mdr
• National Information Exchange Model http://www.niem.gov
• National Science Digital Library (NSDL) Metadata Registry http://metadataregistry.org
• NIST ebXML Registry for HL7 / HIMSS / IHE http://hcxw2k1.nist.gov:8080/
• US Department of Defense Metadata Registry (requires sponsored registration) http://metadata.dod.mil
• US Environmental Protection Agency - Environmental Data Registry http://www.epa.gov/edr

Metadata registry vendors / solutions

In alphabetical order:

• Data Foundations Metadata Registry
• InfoLibrarian Metadata Integration Framework
• Masai Technologies M:Scan GRID
• SAS Metadata Repository
• The Society of Motion Picture and Television Engineers Metadata Dictionary; Registry of Metadata Element Descriptions
• freebXML Registry, A royalty-free open source project implementing OASIS ebXML RegRep standard
• Wellfeet Software's WellGEO RegREP product provides an integrated Registry and Repository specialized for Geographical Information (GI) managament

See also

In alphabetical order:

• Controlled vocabulary
• Data dictionary
• Data element
• Domain Specific Language (DSL)
• Domain-Specific Modeling (DSM)
• ebXML RegRep (ebXML Registry and Repository)
• Global Justice XML Data Model (GJXDM or Global JXDM)
• ISO/IEC 11179
• ISO 15000
• Meta-Object Facility (MOF)
• Metadata
• Metadata publishing
• Metamodeling
• Model Transformation Language (MTL)
• Model-based testing (MBT)
• Model-driven engineering
• National Information Exchange Model (NIEM)
• Object Constraint Language (OCL)
• Ontology (computer science)
• Queries/Views/Transformation (QVT)
• VIsual Automated model TRAnsformation (VIATRA)
• XML Metadata Interchange (XMI)

References

Open Forums on Metadata Registries, in reverse chronological order:

• 10th International Forum on Metadata Registries (2007 - NYC,USA)
• 9th International Forum on Metadata Registries (2006 - Kobe, Japan)
• 8th International Forum on Metadata Registries (2005 - Berlin, Germany)
• 7th International Forum on Metadata Registries (2004 - Xian, China)

fr:Registre de métadonnées