Transitive Closure Files are not distributed in the SNOMED CT International Release
The file structures documented here are points of reference for those generating transitive closure table from release data. SNOMED International provides a script file that can be used to generate the Snapshot Transitive Closure file from the snapshot Relationship File.
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The 
is the complete set of 
between every 
and each of its super-type 
, in other words both its parents and 
.
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 (click to download) that can be used to generating a snapshot view of the transitive closure from the snapshot release of the 
. The output of this script conforms to the following following file structure. Note that the primary key for this table consists of both columns.
Transitive Closure File - Detailed Specification |
Versioned Transitive Closure
A versioned view of the can 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.
Versioned Transitive Closure File - Example Specification |
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