Technical information
Zthes
The Zthes family of specifications includes an XML format for the description and transmission of thesauri, vocabularies and other classification schemes as described in ISO 2788 and ANSI/NISO Z39.19.
Zthes XML format version 1.0 has been adopted as the technical standard for the publication of controlled vocabularies used in the education sector. The use of a published, open standard provides the interoperability that is a core aim of Becta's vocabulary management services.
A vocabulary is expressed in Zthes using three main elements:
- Vocabulary data: information about the vocabulary or thesaurus itself.
For example, vocabulary name = ACLearn, vocabulary identifier = 0002-ACL, description = Adult and Community Learning The Adult Community Learning vocabulary. - Terms: classification elements.
For example, term name = water cycle, which has the term identifier = Gg-0076. Each term may have additional information associated with it such as a type or description. - Relationships: connections between terms.
For example, linguistic equivalent. Some relationships are automatically paired, broader term and narrower term for instance.
Web Services
The SRU (Search, Retrieve, URL) protocol is used to access the Vocabulary Bank directly by using its standards-based access mechanism. This enables queries to be expressed in URL query strings to retrieve metadata from remote hosts.
See the terms and conditions for using the web service to access the Vocabulary Bank directly [PDF 60KB].
See the user guide for an introduction to using this interface to construct queries.
Identifiers
No two items can have the same identifer.
Each authority in Vocabulary Studio has a unique name and number (authority identifier).Authorities control only their own terms and vocabularies and must give them their own name and identifier (local identifier). These local identifiers can be generated automatically by the Studio if users do not have their own naming system.
Vocabulary Studio creates a system wide unique identifier by combining the authority identifier and the local identifier. Global identifiers are always unique in the Studio and the Bank, and are not duplicated or reused.
This system of identification is necessary because a word or phrase may mean different things in different vocabularies, and several users may use the same identifiers for different things. Terms can be resolved by using their globally unique identifier in the Bank, but users can choose to keep their own identification systems and services.
Further information
Zthes application profile PDF [164 KB] A full profile of how Zthes XML format, version 1.0, has been applied to vocabularies published through Becta's Vocabulary Studio is available for download.
Zthes website For information about Zthes and the scheme.
Library of Congress website The web site for information about SRU, a mechanism used to query Bank.
Helpdesk If you have any queries about the technical operation of Vocabulary Bank please contact us.