###### 3.1.5.1.17 subjectRelHeader

The <subjectRelHeader> element specifies the roles played by subjects in associations.

You use the subjectRelHeader element to supply a header row for a subject relationship table when you want to identify the roles played by the subjects in each column. Each cell in the header row identifies a subject topic that defines a role. When specializing the subjectRelTable element, you can accomplish the same purpose by specializing the cells within the rows to enforce the roles.

###### Contains

Doctype | Content model
subjectScheme | ( (subjectRole) (one or more) )

###### Contained by

Doctype | Content model
subjectScheme | subjectRelTable

###### Inheritance

- map/relrow subjectScheme/subjectRelHeader

###### Example

The subject relationship table in this example establishes environmentFor relationships between operating systems and applications. Based on the subjectRole element, subjects in the first column are operating systems which are the environment for an application, while subjects in the second column are applications that run in that environment. For a user interested in content about the operating system, content about the applications may also be relevant.

    <subjectScheme>
      <hasKind>
        <subjectdef keys="operatingSystem">
            <subjectdef keys="linuxOS"/>
            <subjectdef keys="windowsOS"/>
        </subjectdef>
        <subjectdef keys="application">
            <subjectdef keys="IDE">
                <subjectdef keys="eclipseIDE"/>
                <subjectdef keys="visualStudioIDE"/>
            </subjectdef>
            <subjectdef keys="webBrowser">
                <subjectdef keys="firefoxBrowser"/>
                <subjectdef keys="ieBrowser"/>
            </subjectdef>
        </subjectdef>
      </hasKind>
      ...
      <subjectRelTable>
        <subjectRelHeader>
          <subjectRole>
            <subjectdef keyref="operatingSystem">
              <hasRelated keyref="environmentFor">
                <subjectdef keyref="application"/>
              </hasRelated>
            </subjectdef>
          </subjectRole>
          <subjectRole>
            <subjectdef keyref="application"/>
          </subjectRole>
        </subjectRelHeader>
        <subjectRel>
          <subjectRole>
            <subjectdef keyref="linuxOS"/>
            <subjectdef keyref="windowsOS"/>
          </subjectRole>
          <subjectRole>
            <subjectdef keyref="eclipseIDE"/>
            <subjectdef keyref="firefoxBrowser"/>
          </subjectRole>
        </subjectRel>
        <subjectRel>
          <subjectRole>
            <subjectdef keyref="windowsOS"/>
          </subjectRole>
          <subjectRole>
            <subjectdef keyref="ieBrowser"/>
            <subjectdef keyref="visualStudioIDE"/>
          </subjectRole>
        </subjectRel>
      </subjectRelTable>
    </subjectScheme>

A table view of the subjectRelTable may look like this; each <subjectRel> represents a single row, and each <subjectRole> represents a cell.

subjectRelTable as a table

    <subjectdef keyref="operatingSystem">
     <hasRelated keyref="environmentFor">
      <subjectdef keyref="application"/>
     </hasRelated>
    </subjectdef>
    <subjectdef keyref="application"/>
<subjectdef keyref="linuxOS"/> <subjectdef keyref="windowsOS"/> | <subjectdef keyref="eclipseIDE"/> <subjectdef keyref="firefoxBrowser"/>
<subjectdef keyref="windowsOS"/> | <subjectdef keyref="ieBrowser"/> <subjectdef keyref="visualStudioIDE"/>

###### Attributes

Name | Description | Data Type | Default Value | Required?
univ-atts attribute group (includes select-atts, id-atts, and localization-atts groups) | A set of related attributes, described in 3.4.1.3 univ-atts attribute group |  |  |
global-atts attribute group (xtrf, xtrc) | A set of related attributes, described in 3.4.1.2 global-atts attribute group |  |  |
class | A common attribute described in 3.4.1.9 Other common DITA attributes |  |  |

Previous Topic: 3.1.5.1.16 subjectRelTable

Next Topic: 3.1.5.1.18 subjectRel

Parent Topic: 3.1.5.1 Subject scheme maps

Sibling Topics:

3.1.5.1.1 subjectScheme

3.1.5.1.2 schemeref

3.1.5.1.3 hasInstance

3.1.5.1.4 hasKind

3.1.5.1.5 hasNarrower

3.1.5.1.6 hasPart

3.1.5.1.7 hasRelated

3.1.5.1.8 enumerationdef

3.1.5.1.9 elementdef

3.1.5.1.10 attributedef

3.1.5.1.11 defaultSubject

3.1.5.1.12 subjectHead

3.1.5.1.13 subjectHeadMeta

3.1.5.1.14 subjectdef

3.1.5.1.15 relatedSubjects

3.1.5.1.16 subjectRelTable

3.1.5.1.18 subjectRel

3.1.5.1.19 subjectRole