# SNOMED CT RF2 & ref sets - UML and meta-data diagrams

**Category:** [Technical (archive)](https://discourse.openehr.org/c/technical-archive/156)
**Created:** 2010-03-16 16:01 UTC
**Views:** 3
**Replies:** 2
**URL:** https://discourse.openehr.org/t/snomed-ct-rf2-ref-sets-uml-and-meta-data-diagrams/14976

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## Post #1 by @thomas.beale

As part of reviewing SNOMED CT Release Format 2 (RF2) and Reference Sets specifications, I have created some diagrams which are available here: [http://www.openehr.org/wiki/pages/viewpageattachments.action?pageId=10387459](http://www.openehr.org/wiki/pages/viewpageattachments.action?pageId=10387459)

So far I have a class diagram, and semantic net diagrams of the SNOMED meta-data hierarchy. The latter is really a meta-model hierarchy, used to define the model of other parts of Snomed.

I am still refining the original .vsd, but it is available if anyone wants it.

- thomas beale

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## Post #2 by @mikael

Hi Thomas,

Since January 2010 is the status “Limited” is handled as an inactive value. (See SNOMED CT Technical Reference Guide Appendix B.)

Greetings,

Mikael

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## Post #3 by @thomas.beale

thanks Mikael, I have fixed this and various other errors, and improved (according to me ;-) the visual appearance. See [http://www.openehr.org/wiki/pages/viewpageattachments.action?pageId=10387459&sortBy=date&highlight=RF2_meta_data-ref_set_attr.png&](http://www.openehr.org/wiki/pages/viewpageattachments.action?pageId=10387459&sortBy=date&highlight=RF2_meta_data-ref_set_attr.png&)

- thomas beale

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