# Constraints on Issuer and assigner in DV\_Identifier

**URL:** <https://discourse.openehr.org/t/constraints-on-issuer-and-assigner-in-dv-identifier/6509>\
**Category:** LinkEHR\
**Created:** [3 March 2025 16:03 UTC](https://discourse.openehr.org/t/constraints-on-issuer-and-assigner-in-dv-identifier/6509 "2025-03-03T16:03:52Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![birger.haarbrandt](https://discourse.openehr.org/user_avatar/discourse.openehr.org/birger.haarbrandt/32/24_2.png) [@birger.haarbrandt](https://discourse.openehr.org/u/birger.haarbrandt)\
**Post date:** [3 March 2025 16:03 UTC](https://discourse.openehr.org/t/constraints-on-issuer-and-assigner-in-dv-identifier/6509/1 "2025-03-03T16:03:52Z")

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Hi everybody,

I’m currently working on a template which stores implant data. There is a code called UDI ([Unique Device Identifier - UDI - European Commission](https://health.ec.europa.eu/medical-devices-topics-interest/unique-device-identifier-udi_en)) to identify the medical device. There is only a small list of eligible issuers for the UDIs and therefore I would like to put a constraint on mentioned field(s).

To me it looks like setting the constraints is not supported by the UI in LinkEHR or Archetype Designer. Also, it would be nice to be able to provide a Regex as part of the validation. So I wanted to check if this a correct observation that this is supported by the AM but not the tools at the moment.

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**Author:** ![yampeku](https://discourse.openehr.org/user_avatar/discourse.openehr.org/yampeku/32/25_2.png) [@yampeku](https://discourse.openehr.org/u/yampeku)\
**Post date:** [3 March 2025 16:19 UTC](https://discourse.openehr.org/t/constraints-on-issuer-and-assigner-in-dv-identifier/6509/2 "2025-03-03T16:19:29Z")

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LinkEHR probably does not support this in the openEHR specific editor, but you should be able to define that regex string constraint in the general tree editor

 ![imagen](https://discourse.openehr.org/uploads/default/original/2X/3/38dcd4f3bb4fd4e0c8388d4e7cd3a059bfcbbdbc.png)

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**Author:** ![birger.haarbrandt](https://discourse.openehr.org/user_avatar/discourse.openehr.org/birger.haarbrandt/32/24_2.png) [@birger.haarbrandt](https://discourse.openehr.org/u/birger.haarbrandt)\
**Post date:** [3 March 2025 16:24 UTC](https://discourse.openehr.org/t/constraints-on-issuer-and-assigner-in-dv-identifier/6509/3 "2025-03-03T16:24:45Z")

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Perfect, thanks a lot, I indeed looked in the wrong place!