Purpose

An 900000000000521006 $$ Association type reference set $$ represents a set of unordered associations of a particular type between components .

Data structure

An Association reference set is a Component reference set used to represent associations between component . Its structure is shown in the following table.

Table 50. Association 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 900000000000521006 $$ Association type reference set $$. This indicates the nature of the association between the source and target components .
referencedComponentId	SCTID	The identifier of the source component of the association.
targetComponentId	SCTID	The identifier of the target component of the association.

Metadata

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

900000000000455006 $$ Reference set $$
- 900000000000521006 $$ Association type $$
  - 900000000000522004 $$ Historical association $$

Figure 16. Association Reference Sets in the Metadata Hierarchy

Notes on usage

Each member of a $$ Historical association $$ reference set represents a Reference from an inactive component to other equivalent or related components that were current in the Release Version in which that component was inactivated.
Each $$ Historical association $$ reference set holds Relationships of a different nature between the components. The |Historical association| reference sets contains associations:

from each inactive description to one or more other Descriptions that are current in the release Version in which the description was inactivated;
from each inactive reference set for which there is a current replacement to the replacement reference set ;
from an inactive description to a concept that is current in the Release Version in which the description was inactivated, and which is correctly described by the Term of the inactive description ;
From each inactive concept to one or more concepts that replace it.

The component identified by the targetComponentId must be an instance of the same class of component as the component identified by the referencedComponentIdfor all |Historical association| reference sets apart from the |REFERS TO concept association reference set |.
Within the |REFERS TO concept association reference set |, the referenced ComponentId field must be a description and the targetComponentIdmust be a concept .
The targetComponentId is used differently in the |MOVED TO association reference set |. In this case, the targetComponentId does not refer directly to a replacement component, but rather to the namespace to which the component was moved to. The targetComponentId actually refers to the concept that represents the namespace. This approach is used since the organization sourcing the component may not always be able to determine the precise reference that is applicable in the receiving organization (namespace). Thus the responsibility for these references lies with the new responsible (receiving) organization .

Descriptor template and examples

The tables below show examples of the descriptors for specific reference sets that follow the 900000000000521006 $$ Association type reference set $$ pattern.

Table 51. Refset Descriptor rows for 900000000000527005 $$ SAME AS association reference set $$ .
refsetId	referencedComponentId (Referenced component)	attributeDescription (Attribute description)	attributeType (Attribute type)	attributeOrder (Attribute order)
900000000000456007 $$ Reference set descriptor $$	900000000000527005 $$ SAME AS association reference set $$	900000000000532006 $$ Association source component $$	900000000000460005 $$ Component type $$	0
900000000000456007 $$ Reference set descriptor $$	900000000000527005 $$ SAME AS association reference set $$	900000000000533001 $$ Association target component $$	900000000000460005 $$ Component type $$	1
Table 52. Refset Descriptor rows for 900000000000531004 $$ REFERS TO concept association reference set $$ .
refsetId	referencedComponentId (Referenced component)	attributeDescription (Attribute description)	attributeType (Attribute type)	attributeOrder (Attribute order)
900000000000456007 $$ Reference set descriptor $$	900000000000531004 $$ REFERS TO concept association reference set $$	900000000000532006 $$ Association source component $$	900000000000460005 $$ Component type $$	0
900000000000456007 $$ Reference set descriptor $$	900000000000531004 $$ REFERS TO concept association reference set $$	900000000000533001 $$ Association target component $$	900000000000460005 $$ Component type $$	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 .

Association reference set example

The following table holds example entries for the $$ Replaced by $$ reference set .

Table 53. Sample content from 900000000000526001 $$ REPLACED BY association reference set $$ .
refsetId	referencedComponentId (Association source component)	targetComponentId (Association target component)
900000000000526001 $$ REPLACED BY association reference set $$	100005 $$ SNOMED RT Concept $$	138875005 $$ SNOMED CT Concept $$
900000000000526001 $$ REPLACED BY association reference set $$	212002 $$ Salmonella III arizonae 53:k:z $$	398450001 $$ Salmonella IIIb 53:k:z $$
900000000000526001 $$ REPLACED BY association reference set $$	225005 $$ Special care of patient with contagious disease $$	133895001 $$ Care of patient with infectious disease $$
900000000000526001 $$ REPLACED BY association reference set $$	244003 $$ Evans and Lloyd-Thomas syndrome $$	66659007 $$ Normal variation in position $$
900000000000526001 $$ REPLACED BY association reference set $$	278009 $$ Epidural injection of neurolytic substance, lumbar $$	17753007 $$ Epidural injection of neurolytic solution, lumbar $$
900000000000526001 $$ REPLACED BY association reference set $$	558000 $$ Other disorder of the neurohypophysis, NEC $$	72442006 $$ Disorder of posterior pituitary $$
900000000000526001 $$ REPLACED BY association reference set $$	659001 $$ Peptostreptococcus anaerobius $$	413524006 $$ Anaerococcus tretradius $$
900000000000526001 $$ REPLACED BY association reference set $$	696005 $$ Chronobiologic disorder $$	387605007 $$ Abnormal chronobiologic state $$
900000000000526001 $$ REPLACED BY association reference set $$	700002 $$ Salmonella III arizonae 50:z4,z23,z32:-- $$	404619004 $$ Salmonella IIIa 50:z4,z23,z32:- $$
900000000000526001 $$ REPLACED BY association reference set $$	822000 $$ Salmonella arizonae 53:z4,z23:-- $$	13998005 $$ Salmonella IV 53:z4,z23:-- $$