<subjectdef>
The <subjectdef> also can use a <navtitle> element to supply a label for the subject or the @href attribute to reference a topic that captures the consensus definition for the subject.
As with normal <topicref> processing, when the <subjectdef> element specifies a <navtitle> and refers to a topic, processors should use the actual topic title in place of the <navtitle>. To use the <navtitle> as a subject label, set the @locktitle attribute on the <subjectdef> element to "yes".
Content models
See appendix for information about this element in OASIS document type shells.
Inheritance
- map/topicref subjectScheme/subjectdef
Example
<subjectScheme>
<!-- Pull in a scheme that defines unix OS values -->
<schemeref href="unixOS.ditamap"/>
<!-- Define new OS values that are merged with those in the unixOS scheme -->
<subjectdef keys="os">
<subjectdef keys="linux"/>
<subjectdef keys="mswin"/>
<subjectdef keys="zos"/>
</subjectdef>
<!-- Define application values -->
<subjectdef keys="app" navtitle="Applications">
<subjectdef keys="apacheserv" href="subject/apache.dita"/>
<subjectdef keys="mysql" href="subject/sql.dita"/>
</subjectdef>
<!-- Define an enumeration of the platform attribute, equal to
each value in the OS subject. This makes the following values
valid for the platform attribute: linux, mswin, zos -->
<enumerationdef>
<attributedef name="platform"/>
<subjectdef keyref="os"/>
</enumerationdef>
<!-- Define an enumeration of the otherprops attribute, equal to
each value in the application subjects.
This makes the following values valid for the otherprops attribute:
apacheserv, mysql -->
<enumerationdef>
<attributedef name="otherprops"/>
<subjectdef keyref="app"/>
</enumerationdef>
</subjectScheme>
Attributes
The following attributes are available on this element: Universal attribute group, Topicref element attributes group, Link relationship attribute group (with a narrowed definition of @href, given below), @outputclass, @keys, and @keyref. This element also uses @processing-role, @toc, @collection-type, @linking, and @locktitle from Attributes common to many map elements.
- @href
- A pointer to the resource represented by the <topicref>. See The @href attribute for detailed information on supported values and processing implications. References to DITA content cannot be below the topic level: that is, you cannot reference individual elements inside a topic. References to content other than DITA topics should use the @format attribute to identify the kind of resource being referenced.