Hierarchy

Overview

Hierarchys are a separate structure used for describing complex hierarchies of codes, potentially including codes from multiple different codelists. Software tools designed for users to explore and search a catalogue of data sets typically use a Hierarchical Codelists to display a tree structure much like Windows File Explorer.

In SDMX 2.1, Hierarchy Codelists do not explicitly link to any other structures like Dataflows. As such, the result of a user choosing a code is left entirely to the designers of the tools.

The principal features of the Hierarchy Codelists' are:

• A child code can have more than one parent.
• There can be more than one code that has no parent (known as Root codes in the Registry).
• There may be many hierarchies (or “views”) defined, in terms of the associations between the codes. Each hierarchy serves a particular purpose in the reporting, analysis, or dissemination of data.
• The levels in a hierarchy can be explicitly defined or they can be implicit: (i.e., they exist only as parent/child relationships in the coding structure).

Structure Properties

Structure Type	Standard SDMX Structural Metadata Artefact
Maintainable	Yes
Identifiable	Yes
Item Scheme	Yes
SDMX Information Model Versions	3.0
URN - Codelist namespace	urn:sdmx:org.sdmx.infomodel.codelist.Hierarchy
URN - Code namespace	urn:sdmx:org.sdmx.infomodel.codelist.Code

Context within the SDMX 3.0 Information Model