# Description Format Reference Set

## Purpose

The [900000000000538005 |Description format reference set|](http://snomed.info/id/900000000000538005) specifies the text format and maximum length of each supported description type. This permits additional description types to be specified in future in addition to the three existing description types ( synonym, fully specified name and textual definition).

## Data structure

The [900000000000538005 |Description format reference set|](http://snomed.info/id/900000000000538005) is a C-I ( component- Integer) reference set which is used to specify the length and format of the terms in descriptions of this description type. Its structure is shown in the following table.

**Description format reference set - Data structure**

<table data-full-width="true"><thead><tr><th>Field</th><th>Data type</th><th>Purpose</th><th>Mutable</th><th>PK*</th></tr></thead><tbody><tr><td>id</td><td>UUID</td><td><p>A 128 bit unsigned Integer, uniquely identifying this reference set member.</p><p>Different versions of a <em>reference set member</em> share the same id but have different effectiveTime. This allows a <em>reference set member</em> to be modified or made inactive (i.e. removed from the active set) at a specified time.</p></td><td><strong>NO</strong></td><td><strong>YES</strong><br>(Full /Snapshot)</td></tr><tr><td>effectiveTime</td><td>Time</td><td><p>The inclusive date or time at which this version of the identified reference set member became the current version.</p><p><strong>Note</strong>: In distribution files the effectiveTime should follow the short ISO date format (<em>YYYYMMDD</em>) and should not include the hours, minutes, seconds or timezone indicator.</p><p>The current version of this reference set member at time <em>T</em> is the version with the most recent effectiveTime prior to or equal to time <em>T</em>.</p></td><td><strong>YES</strong></td><td><p><strong>YES</strong><br>(Full)</p><p>Optional (Snapshot)</p></td></tr><tr><td>active</td><td>Boolean</td><td><p>The state of the identified reference set member as at the specified effectiveTime .</p><p>If active = 1 (true) the reference set member is part of the current version of the set, if active = 0 (false) the reference set member is not part of the current version of the set.</p></td><td><strong>YES</strong></td><td><strong>NO</strong></td></tr><tr><td>moduleId</td><td>SCTID</td><td><p>Identifies the SNOMED CT module that contains this reference set member as at the specified effectiveTime .</p><p>The value must be a subtype of <a href="http://snomed.info/id/900000000000443000">900000000000443000 |Module (core metadata concept)|</a> within the metadata hierarchy.</p></td><td><strong>YES</strong></td><td><strong>NO</strong></td></tr><tr><td>refsetId</td><td>SCTID</td><td><p>Identifies the reference set to which this reference set member belongs.</p><p>In this case, a subtype descendant of: <a href="http://snomed.info/id/900000000000538005">900000000000538005 |Description format reference set (foundation metadata concept)|</a></p></td><td><strong>NO</strong></td><td><strong>NO</strong></td></tr><tr><td>referencedComponentId</td><td>SCTID</td><td><p>A reference to the SNOMED CT component to be included in the reference set.</p><p>Refers to the concept that represents the description type for which this row defines the format.</p></td><td><strong>NO</strong></td><td><strong>NO</strong></td></tr><tr><td>descriptionFormat</td><td>SCTID</td><td>A reference to a subtype of <a href="http://snomed.info/id/900000000000539002">900000000000539002 |Description format (foundation metadata concept)|</a> attribute which specifies the format of terms in descriptions of this description type.</td><td><strong>NO</strong></td><td><strong>NO</strong></td></tr><tr><td>descriptionLength</td><td>Integer</td><td>The maximum length in bytes of the terms in descriptions of this description type.</td><td><strong>NO</strong></td><td><strong>NO</strong></td></tr></tbody></table>

{% hint style="info" %}
PK\* indicates if the attribute is part of the primary key for that file/table.
{% endhint %}

***

## Metadata

The following metadata supports the description format reference set:

**Description Format Reference Set in the Metadata Hierarchy**

> [9](http://snomed.info/id/900000000000454005)[900000000000454005 |Foundation metadata concept|](http://snomed.info/id/900000000000454005)\
> [900000000000455006 |Reference set|](http://snomed.info/id/900000000000455006)\
> [900000000000538005 |Description format|](http://snomed.info/id/900000000000538005)

***

## Reference Set Descriptor and Example Data

{% hint style="info" %}
**Notes on the tables used to show descriptors and examples**

The reference set example tables on this page have been revised as follows to aid clarity and understanding:

* The first four columns which are present in all release files are not shown. The omitted columns (id, effectiveTime, active, moduleId) are used in the same way in all referenced sets to support identification, versioning and packaging. They do not directly affect the specific features of a particular reference set or reference set type.
* Reference set columns that contain SNOMED CT identifiers are expanded to show details of the concept or description referenced by that identifier. In some cases, the term is shown in the same column using the expression syntax, in other cases an additional column with a name suffix '\_term' has been added. In the standard reference set files only the identifier is present in the column and there is no added column for the term. When using reference sets, the term and other details of the component are looked up from the relevant component release files.
  {% endhint %}

### Descriptor

The table below shows the descriptor that defines the structure of the [900000000000538005 |Description format reference set|](http://snomed.info/id/900000000000538005) .

**Refset Descriptor rows for Description Format Reference Set**

<table data-full-width="true"><thead><tr><th>refsetId</th><th>referencedComponentId (Referenced component)</th><th>attributeDescription (Attribute description)</th><th>attributeType (Attribute type)</th><th>attributeOrder (Attribute order)</th></tr></thead><tbody><tr><td><a href="http://snomed.info/id/900000000000456007">900000000000456007 |Reference set descriptor|</a></td><td><a href="http://snomed.info/id/900000000000538005">900000000000538005 |Description format|</a></td><td><a href="http://snomed.info/id/900000000000462002">900000000000462002 |Description type component|</a></td><td><a href="http://snomed.info/id/900000000000461009">900000000000461009 |Concept type component|</a></td><td>0</td></tr><tr><td><a href="http://snomed.info/id/900000000000456007">900000000000456007 |Reference set descriptor|</a></td><td><a href="http://snomed.info/id/900000000000538005">900000000000538005 |Description format|</a></td><td><a href="http://snomed.info/id/900000000000539002">900000000000539002 |Description format|</a></td><td><a href="http://snomed.info/id/900000000000461009">900000000000461009 |Concept type component|</a></td><td>1</td></tr><tr><td><a href="http://snomed.info/id/900000000000456007">900000000000456007 |Reference set descriptor|</a></td><td><a href="http://snomed.info/id/900000000000538005">900000000000538005 |Description format|</a></td><td><a href="http://snomed.info/id/900000000000544009">900000000000544009 |Description length|</a></td><td><a href="http://snomed.info/id/900000000000478000">900000000000478000 |Unsigned integer|</a></td><td>2</td></tr></tbody></table>

***

#### Example Data

This example holds the all the members of the [900000000000538005 |Description format reference set|](http://snomed.info/id/900000000000538005) in the SNOMED CT International Release for July 2014. Other members may added to future versions of the International Release if new description types are introduced. Owners of Extensions that support additional description types must also add members to the [900000000000538005 |Description format reference set|](http://snomed.info/id/900000000000538005) .

**Sample Content from the Description Format Reference Set**

<table data-full-width="true"><thead><tr><th>refsetId</th><th>referencedComponentId (Description type component)</th><th>descriptionFormat (Description format)</th><th>descriptionLength (Description length)</th></tr></thead><tbody><tr><td><a href="http://snomed.info/id/900000000000538005">900000000000538005 |Description format|</a></td><td><a href="http://snomed.info/id/900000000000003001">900000000000003001 |Fully specified name|</a></td><td><a href="http://snomed.info/id/900000000000540000">900000000000540000 |Plain text|</a></td><td>255</td></tr><tr><td><a href="http://snomed.info/id/900000000000538005">900000000000538005 |Description format|</a></td><td><a href="http://snomed.info/id/900000000000013009">900000000000013009 |Synonym|</a></td><td><a href="http://snomed.info/id/900000000000540000">900000000000540000 |Plain text|</a></td><td>255</td></tr><tr><td><a href="http://snomed.info/id/900000000000538005">900000000000538005 |Description format|</a></td><td><a href="http://snomed.info/id/900000000000550004">900000000000550004 |Definition|</a></td><td><a href="http://snomed.info/id/900000000000540000">900000000000540000 |Plain text|</a></td><td>4096</td></tr></tbody></table>

***

{% hint style="info" %}
Note: The tables above omit the initial four columns of data present in the release file. These follow the standards versioning pattern id, effectiveTime, active, moduleId. Additionally, to aid understanding, the tables above also show the term from one of the descriptions associated with each of the identified concept. The release file only contains the identifier.
{% endhint %}

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