# How is the "constraint reference" used in "magnitude\_status" within the "Dv\_Quantity" in openEHR?

**URL:** https://discourse.openehr.org/t/how-is-the-constraint-reference-used-in-magnitude-status-within-the-dv-quantity-in-openehr/4329
**Category:** Clinical
**Tags:** archetype
**Created:** [9 August 2023 14:49 UTC](https://discourse.openehr.org/t/how-is-the-constraint-reference-used-in-magnitude-status-within-the-dv-quantity-in-openehr/4329 "2023-08-09T14:49:01Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![Zahra\_Ghaempanah](https://discourse.openehr.org/letter_avatar_proxy/v4/letter/z/3e96dc/32.png) [@Zahra\_Ghaempanah](https://discourse.openehr.org/u/Zahra_Ghaempanah)
#### Post date: [9 August 2023 14:49 UTC](https://discourse.openehr.org/t/how-is-the-constraint-reference-used-in-magnitude-status-within-the-dv-quantity-in-openehr/4329/1 "2023-08-09T14:49:02Z")

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hello everyone,  
How is the “constraint reference” used in “magnitude\_status” within the “Dv\_Quantity” in openEHR? Could everyone provide an example?

 ![image](https://discourse.openehr.org/uploads/default/original/2X/8/80f0e608c6b1785d137b173b55e040c778bcfdca.png)

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### Author: ![damoca](https://discourse.openehr.org/user_avatar/discourse.openehr.org/damoca/32/2606_2.png) [@damoca](https://discourse.openehr.org/u/damoca)
#### Post date: [14 August 2023 12:17 UTC](https://discourse.openehr.org/t/how-is-the-constraint-reference-used-in-magnitude-status-within-the-dv-quantity-in-openehr/4329/2 "2023-08-14T12:17:13Z")

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Since the possible values for that “magnitude\_status” are just Strings of the mathematical symbols, it has little sense to use a constraint reference (acNNNN codes) in that attribute.

 ![image](https://discourse.openehr.org/uploads/default/original/2X/7/7f183c5660a6262e5b8a88bd3ce8a8e7b5b92084.png)

It would be useful if it had been initially defined in the reference model as a terminological code, for example a subset made of these SNOMED CT values:

 ![image](https://discourse.openehr.org/uploads/default/original/2X/b/bd9488f7221f59ea0153f6682fb941174b21ae61.png)

> **[SNOMED International Browser](https://browser.ihtsdotools.org/?perspective=full&conceptId1=276135000&edition=MAIN%2F2023-07-31&release=&languages=en)**
>
> SNOMED International SNOMED CT Browser

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### Author: ![thomas.beale](https://discourse.openehr.org/user_avatar/discourse.openehr.org/thomas.beale/32/35_2.png) [@thomas.beale](https://discourse.openehr.org/u/thomas.beale)
#### Post date: [15 August 2023 02:42 UTC](https://discourse.openehr.org/t/how-is-the-constraint-reference-used-in-magnitude-status-within-the-dv-quantity-in-openehr/4329/3 "2023-08-15T02:42:33Z")

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It would have been better if we had used a built-in enum I think, since that would have mapped to integers in most languages. Although we don’t have a meta-type for constraining ‘enums’ as such… something to think about for next ADL version…