MDId

MDId is a term used in information management to denote a persistent identifier associated with metadata-bearing digital objects. It is not a single standardized specification; rather, MDId serves as an umbrella concept across domains where stable references to digital items are needed. In practice, an MDId functions as a globally unique reference that enables reliable citation, discovery, and interoperability among systems that store, describe, or deliver digital assets.

Key characteristics of an MDId include persistence, uniqueness, and resolvability. An MDId is typically composed of a namespace or prefix and a local identifier, and it may be represented as a URI, DOI, Handle, ARK, or another persistent-identifier form. It is usually carried in metadata records and used to link related data across catalogs, repositories, and publication platforms. The goal is to decouple the identifier from the object’s location, so the MDId remains valid even if the underlying storage changes.

Common use cases span digital libraries, archives, and museums, where MDId-like identifiers reference digital assets such as documents, images, and audiovisual materials. Data repositories and research information systems also employ MDIds to connect datasets to metadata, provenance records, and related resources, supporting reproducibility and integrated discovery.

Governance and lifecycle considerations are central to MDId practice. Assigning authorities establish naming rules, ownership, versioning, and deprecation policies. Systems typically support dereferencing—providing metadata or landing pages when an MDId is resolved. When aligned with broader standards (for example, DOIs or URIs) MDIds enhance interoperability across platforms and disciplines.

See also: Persistent identifier, DOI, URI, Handle, ARK, metadata registry.