###### 3.1.5.2.4 topicSubjectTable

The <topicSubjectTable> element is a specialized relationship table which allows a map to use relationship tables to associate topics with subjects. Tools (such as search tools) may use these classifications to retrieve content that is relative to a specific subject or combination of subjects.

In a <topicSubjectTable>, the first column is reserved for references to content. Subsequent columns are reserved for subjects that classify the content, each column supplying the subjects for a different category as identified in the header. The table resembles a traditional relationship table in which the first column identifies the source and the other columns identify the targets, but the relationship reflects the subjects covered by the content rather than linking between documents.

In a traditional reltable, topics in any given column establish relationships with topics in every other cell of the same row. In a <topicSubjectTable>, topics in the first column are related to all of the subjects in the row, but no relationship is implied between subjects in different columns of the same row. Instead, relationships are defined between subjects using a subject scheme map (which provides a <subjectRelTable> element for non-hierarchical relationships between subjects).

###### Contains

Doctype | Content model
classifyMap | ( (title) then (topicmeta) (optional) then (topicSubjectHeader) (optional) then (topicSubjectRow) (one or more) )

###### Contained by

Doctype | Content model
classifyMap | map

###### Inheritance

+ map/reltable classify-d/topicSubjectTable

###### Example

The topic subject table below classifies topics with goals for retrieval and with operating systems for filtering. The map makes use of definitions in a subject scheme map, defined separately.

Figure 3-33 Subject scheme map

    <subjectScheme>
        <hasKind>
            <subjectdef href="goalType.dita" keys="goal">
                <subjectdef href="performanceGoal.dita" keys="performance"/>
                <subjectdef href="reliabilityGoal.dita" keys="reliability"/>
            </subjectdef>
            <subjectdef href="operatingSystem.dita" keys="os">
                <subjectdef href="linuxOS.dita" keys="linux"/>
                <subjectdef href="unixOS.dita" keys="unix"/>
                <subjectdef href="windowsOS.dita" keys="windows"/>
            </subjectdef>
        </hasKind>
    </subjectScheme>

Figure 3-34 Topic subject table

The following <topicSubjectTable> classifies several topics according to subjects in the previous map. As with any <topicSubjectTable>, the first column is used to specify topics. In this specific example, the second column is used to specify a goal, based on the "goal" subject in the header. The third column is used to specify an operating system. Based on those definitions, the following classifications are made by this table:

- The topics "Configuring cron for efficient startup" and "Allocating raw storage" are each classified by the goal of "performance"; in addition, they are classified by the operating systems "linux" and "unix.
- The topics "Analyzing web logs for service issues" and "Detecting denial-of-service attacks" are each classified by the goal of "reliability"; in addition, they are classified by the operating systems "linux", "unix", and "windows".
- No relationship is defined between subjects in the table, meaning that this table does not define any relationship between the goal of "performance" and the operating systems "linux" or "unix".

    <map>
    ...
    <topicSubjectTable>
      <topicSubjectHeader>
        <topicCell type="task"/>
        <subjectCell>
          <topicsubject keyref="goal"/>
        </subjectCell>
        <subjectCell>
          <topicapply keyref="os"/>
        </subjectCell>
      </topicSubjectHeader>
      <topicSubjectRow>
        <topicCell>
          <topicref href="webServerStart.dita" navtitle="Configuring cron for efficient startup"/>
          <topicref href="dbDisk.dita" navtitle="Allocating raw storage"/>
        </topicCell>
        <subjectCell>
          <topicsubject keyref="performance"/>
        </subjectCell>
        <subjectCell>
          <topicapply keyref="linux"/>
          <topicapply keyref="unix"/>
        </subjectCell>
      </topicSubjectRow>
      <topicSubjectRow>
        <topicCell>
          <topicref href="webLogAnalyze.dita" navtitle="Analyzing web logs for service issues"/>
          <topicref href="webDenialService.dita" navtitle="Detecting denial-of-service attacks"/>
        </topicCell>
        <subjectCell>
          <topicsubject keyref="reliability"/>
        </subjectCell>
        <subjectCell>
          <topicapply keyref="linux"/>
          <topicapply keyref="unix"/>
          <topicapply keyref="windows"/>
        </subjectCell>
      </topicSubjectRow>
      ...
    </topicSubjectTable>
    </map>

A table view of this <topicSubjectTable> might look as follows. This is only one of many possible views; to aid in understanding the example, the content topics in the first column are displayed using only their titles, and related subjects are displayed using only their keyref attribute value.

task | goal | os
Configuring cron for efficient startup Allocating raw storage | performance | linux unix
Analyzing web logs for service issues Detecting denial-of-service attacks | reliability | linux unix windows

###### Attributes

Name | Description | Data Type | Default Value | Required?
topicref-atts-no-toc attribute group (collection-type, processing-role, type, scope, locktitle, format, linking, toc, print, search, chunk) | A related set of attributes. See 3.4.1.8 topicref-atts, topicref-atts-no-toc, and topicref-atts-without-format attribute groups. |  |  |
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: 3.1.5.2.3 topicsubject

Next Topic: 3.1.5.2.5 topicSubjectHeader

Parent Topic: 3.1.5.2 Classification domain elements

Sibling Topics:

3.1.5.2.1 subjectref

3.1.5.2.2 topicapply

3.1.5.2.3 topicsubject

3.1.5.2.5 topicSubjectHeader

3.1.5.2.6 topicSubjectRow

3.1.5.2.7 topicCell

3.1.5.2.8 subjectCell