Preview. Built from the published NewsML-G2 documents by tools/prosedoc. This layout is a harness for reviewing structure — it is not the published site.
7. Managing Sets of Concepts - knowledgeItem
An XML Schema file corresponding to the specifications for this item is available (see The Full Set of Specification Documents).
7.1. Description
A knowledgeItem bundles a set of concept components which are managed and exchanged as a whole. A knowledgeItem is used best where a provider wants to circulate a snapshot of a set of entries from one or more controlled vocabularies.
The concepts represented in a knowledgeItem can be of different types, and their identifiers may come from different schemes. A “scheme definition” is therefore a particular case of structure, where all concepts support a concept identifier from a same specific scheme.
Examples of knowledgeItems are the taxonomy of IPTC Subject NewsCodes or an authority list of people’s descriptions maintained by a given provider. Typical characteristics of a knowledgeItem are:
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It contains a set of concepts components covering a specific purpose, e.g. concepts from a single scheme, concept from different schemes and relevent in the context of a specific topic.
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It will usually be updated infrequently but over a long period of time, for example when a controlled vocabulary evolves.
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Its content is of long term interest.
7.2. Structure of a Knowledge Item
The model of a knowledgeItem is very similar to the model of a newsItem. Both share the same indicators of compliance with a standard and conformance level, Identification and Versioning, Signature, Rights Information, Item Metadata and Item links. Please review Representing News - newsItem for more information.
7.2.1. Item Class
The IPTC provides a mandatory standardised scheme applicable to the itemClass property, identified by the URI http://cv.iptc.org/newscodes/cinature/.
7.2.2. Knowledge Related Metadata
Metadata about the whole set of concepts held by a Knowledge Item are wrapped by the contentMeta element.
Metadata about specific concepts held by a Knowledge Item are wrapped by one to many partMeta elements. A typical use case of partMeta is to indicate when several concepts were modified at the same time, by associating those concepts with a specific partMeta which has the associated contentModified property.
The set of administrative metadata is common to all classes of Items.
The set of descriptive metadata for a Knowledge Item is listed below. All properties are optional, repeatable and may be inserted in any order.
Table 9. Descriptive Metadata Core Group Elements
| Element Title | Element Name | Card |
|---|---|---|
Language |
(0..unbounded) |
|
Keyword |
(0..unbounded) |
|
Subject |
(0..unbounded) |
|
Slugline |
(0..unbounded) |
|
Headline |
(0..unbounded) |
|
Description |
(0..unbounded) |
Each provider may add a set of metadata properties which have to be defined in a non-IPTC-G2 namespace. See also XML Namespaces and Extension Points in XML.
Please review News Content Metadata of the News Item chapter for more information.
7.2.3. Metadata Helpers
The knowledgeItem includes three properties which are available to help make metadata assertions:
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the assert property: helps to bundle and extend details of concepts, see Assertions About Concepts
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the inlineRef property: helps to reference concepts which are inline, within free text properties of type label, see References to Inline Concepts.
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the derivedFrom property: helps to document from which concept a concept, used as property value in this item, has been derived, see Document Derivation of Concepts.
7.2.4. Knowledge Item Content
A conceptSet wrapper element contains a set of concept components (see Concept Component). Their order of appearance in conceptSet is not relevant.
Additionally the Concept Set may have an optional schemeMeta child element, which must only be used when the Knowledge Item conveys ALL members of a Scheme. The schemeMeta element supports all attributes of scheme, with the exception of alias and includes the attributes schemecreated, schememodified and schemeretired introduced in NewsML-G2 v2.29.
| All concept definitions share the same catalog of schemes, declared at the top of the Knowledge Item. |