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Creating a Transitive Closure File

SNOMED International provide provides a Perl script that reads the snapshot relationships file. By processing this file, it rapidly generates the transitive closure of all the subtype relationships and then saves this as a file. The result a two column file (subtypeId and supertypeId) containing more than 6.5 million rows. This transitive closure file can then be read into a database table in the same way as the release files.

Using a Transitive Closure File


  • Test is concept A is a subtype of concept B
  • List all supertypes of concept A
  • List all subtype subtypes of concept A.

Computing Proximal Primitive Supertypes


  1. Use the transitive closure table to get the set of all concepts that are supertypes of concept A
    • Call this set: Set-B
  2. Create a subset of Set-B containing only those concepts with definitionStatusId=
    t900000000000074008 |
    • Call this set: Set-C
  3. Create a subset of Set-C containing only those concepts that have no subtypes that are also in Set-C

    Footnote Macro

    Concepts in Set-C that also have subtypes in Set-C are primitive supertypes of concept A but they are not proximal primitive supertypes because these subtype(s) are are more specific concepts that are also primitive supertypes of concept A.

    • The resulting set represents the primitive supertypes of concept A.