Purpose

A 900000000000512005 $$ Query specification type reference set $$ allows a serialised query to represent the membership of a subset of SNOMED CT components. A query contained in the reference set is run against the content of SNOMED CT to produce a subset of concepts, descriptions or relationships. The query is referred to an intensional definition of the subset. It can be run against future releases of SNOMED CT to generate an updated set of subset members.
The members of the resulting subset may also be represented in an enumerated form as a Simple reference set . An enumerated representation of a subset is referred to as an extensional definition.

Data structure

A Query specification reference set is a String reference set containing queries that represent intensional definitions of subsets of components. The result of running the query is an extensional representation of the subset of components which can be represented as a Simple reference set . Its structure is shown in the following table.

Table 43. Query specification reference set - Data structure
Field	Data type	Purpose
id	UUID	A 128 bit unsigned integer, uniquely identifying this reference set member . Different versions of a reference set member share the same id but have different effectiveTimes. This allows a reference set member to be modified or made inactive (i.e. removed from the active set) at a specified time.
effectiveTime	Time	The inclusive date or time at which this version of the identified reference set member became the current version. The current version of this reference set member at time T is the version with the most recent effectiveTime prior to or equal to time T .
active	Boolean	The state of the identified reference set member as at the specified effectiveTime . 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.
moduleId	SCTID	Identifies the SNOMED CT module that contains this reference set member as at the specified effectiveTime . The value must be a subtype of 900000000000443000 $$ Module (core metadata concept) $$ within the metadata hierarchy .
refsetId	SCTID	Identifies the reference set to which this reference set member belongs. In this case, set to a subtype of 900000000000512005 $$ Query specification type $$
referencedComponentId	SCTID	The identifier ( refsetId) of the reference set for which members are to be generated.
query	String	The serialised query that can be used to (re-)generate the reference set members. A standard syntax for use in these queries is currently under development and is due for publication in late 2014.

Metadata

The following metadata in the "Foundation metadata concept " hierarchy supports this reference set :

900000000000454005 $$ Foundation metadata concept $$
- 900000000000455006 $$ Reference set $$
  - 900000000000512005 $$ Query specification type $$
    - 900000000000513000 $$ Simple query specification $$

Figure 14. Hierarchy of Foundation metadata concept

Descriptor template

The table below shows the descriptor that defines the structure of the 900000000000512005 $$ Query specification type reference set $$ pattern.

Table 44. Descriptor Template for Query Specification Reference Sets
refsetId	referencedComponentId	attributeDescription	attributeType	attributeOrder
900000000000456007 $$ Reference set descriptor $$	900000000000512005 $$ Query specification type reference set $$	900000000000514006 $$ Generated reference set $$	900000000000461009 $$ Concept type component $$	0
900000000000456007 $$ Reference set descriptor $$	900000000000512005 $$ Query specification type reference set $$	900000000000515007 $$ Query $$	900000000000465000 $$ String $$	1

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 .

Example usage

In the example below, "serialised query 1" is a text string that can be used to generate members for Reference set 1, which is a simple member reference set (without any additional fields within its member records).

Table 45. Example rows from Query Specification Reference Set
refsetId	referencedComponentId	query
$$ Simple query specification $$	$$ Target reference set $$	Serialized text of the query ...

Query language specification

The specification of the query language has yet to be defined / selected, but it should be capable of:

Selecting concepts using primary fields, subsumption testing, relationships, relationship groups, set operators ( union, intersection, excludes), and lexical query ;
Selecting descriptions, relationships and reference sets using similar mechanisms;
Calculation of values for the reference set 's extended fields. Identifying the version of the syntax and any language syntax variations.
Queries that support definitions for terminologies other than SNOMED CT should also be supported. For example, queries to link or include codes in ICD-10, ICD-11, ICPC and LOINC .

Note: During 2014 work is underway to develop and pilot a standard approach to representation of queries including queries for generation of subset of SNOMED CT concepts .

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Query Specification Reference Set