Postcoordinated Expression Type Reference Set

Purpose

A 1119417006 |Postcoordinated expression type reference set (foundation metadata concept)| provides a standardized way to represent postcoordinated expressions. This representation is useful for the implementation of a postcoordinated expression repository.

Data structure

A 1119460002 |Postcoordinated expression type component (foundation metadata concept)| is a type of |Reference set (foundation metadata concept)| .

Postcoordinated expression type reference set reference set - Data structure

Field	Data type	Purpose	Mutable	PK*
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 effectiveTime. This allows a reference set member to be modified or made inactive (i.e. removed from the active set) at a specified time.	NO	YES (Full /Snapshot)
effectiveTime	Time	The inclusive date or time at which this version of the identified reference set member became the current version. Note: In distribution files the effectiveTime should follow the short ISO date format (YYYYMMDD) and should not include the hours, minutes, seconds or timezone indicator. 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.	YES	YES (Full) Optional (Snapshot)
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.	YES	NO
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.	YES	NO
refsetId	SCTID	Identifies the reference set to which this reference set member belongs. In this case, a subtype descendant of: 900000000000455006| Reference set|	NO	NO
referencedComponentId	SCTID	A reference to the SNOMED CT component to be included in the reference set.	NO	NO
expression	String	A SNOMED CT expression that conforms to the compositional grammar.	YES	NO
substrate	Uniform Resource Identifier	The SNOMED CT content by which the expression is authored.	YES	NO

PK* indicates if the attribute is part of the primary key for that file/table.

---

Metadata

The following metadata hierarchy supports this reference set:

Postcoordinated expression type reference set reference set in the Metadata Hierarchy

900000000000454005 |Foundation metadata concept| 900000000000455006 |Reference set| 1119417006 |Postcoordinated expression type reference set|

---

Reference Set Descriptor and Example Data

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.

Descriptor Template and Examples

The tables below show the descriptor that defines the reference sets that follows the data structure of the |Postcoordinated expression type reference set (foundation metadata concept)| .

Refset Descriptor rows for the postcoordinated expression type reference set.

refsetId	referencedComponentId	attributeDescription	attributeType
900000000000456007 |Reference set descriptor|	1119417006| Postcoordinated expression type reference set (foundation metadata concept)|	449608002 |Referenced component|	91119460002 |Postcoordinated expression type component|	0
900000000000456007 |Reference set descriptor|	1119417006| Postcoordinated expression type reference set (foundation metadata concept)|	1119436001 |Canonical close to user form expression|	1119454002 |Compositional grammar expression|	1
900000000000456007 |Reference set descriptor|	762101119417006| Postcoordinated expression type reference set (foundation metadata concept)|	733616009 |Authoring substrate|	1119461003 |Uniform resource identifier|	2

---

Postcoordinated Expression Type Reference Set Examples

The International Edition of SNOMED CT includes two different types of the |Postcoordinated expression type reference set| . These are the |Canonical close to user form expression reference set (foundation metadata concept)| and |Classifiable form expression reference set (foundation metadata concept)| . Both of these reference sets provide a standardized way of representing different types of SNOMED CT expressions, and are useful for the implementation of a postcoordinated expression repository.

The |Canonical close to user form expression reference set (foundation metadata concept)| provides a standardized way to represent postcoordinated expressions as they were captured by the users, but in a canonical form. The 1119468009 | Classifiable form expression reference set (foundation metadata concept)| provides a standardized way to represent postcoordinated expressions in a classifiable form. The classifiable form is a syntactically valid and concept model compliant representation of the close-to-user form expression, and serves as the input to the classifier, enabling compositional expressions to be classified with SNOMED CT content.