Expression Repository Design

The logical design of an expression repository includes the entities required to hold the data relevant for an expression version.

The image in this page illustrates an expression repository contains one or more expression versions.Each expression version must contain the following data:

  • Versioning data , to represent the time and substrate of the given version of the expression

  • A Close-to-user form expression , to represent the expression as it was stated upon creation

Each expression version should contain the following data:

  • An expression identifier , if this is required to uniquely identify the expression

  • A Classifiable form expression , to enable the generation of the NNF expression

  • A Necessary Normal Form expression , to support querying the expression

All SNOMED CT concepts referenced by expressions in the repository at a particular point in time should all be included, and active, in a specific versioned edition of SNOMED CT.General expression repository design.

General expression repository design.

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