Theis the complete set ofbetween everyand The is the complete set of between every and each of its super-type, in other words both its parents and. A History file can be generated from the content using scripts provided with each release. The generated file will be of the following format and contain the valid states of the of each across all previous releases:

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A transitive closure table is one of the most efficient ways to test for subsumption between concepts.

Snapshot Transitive Closure File

SNOMED International provides an example of a Transitive Closure Perl script file that can be used to generating a snapshot view of the transitive closure from the snapshot release of the relationship file. The output of this script conforms to the following following file structure. Note that the primary key for this table consists of both columns.

Versioned Transitive Closure

A versioned view of thecan also be generated by combining the snapshot views for different effective times and removing redundant rows (e.g. where the transitive closure has not changed between release versions). The generated file could then be represented using the example specification below. Note that the unique key for this file would consist of the subtypeId, supertypeId and effectiveTime.

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Related Links

• 7.5.2 Transitive closure implementation

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