# EHRs with different system\_id in the same server?

**URL:** https://discourse.openehr.org/t/ehrs-with-different-system-id-in-the-same-server/3535
**Category:** RM
**Created:** [6 February 2023 16:43 UTC](https://discourse.openehr.org/t/ehrs-with-different-system-id-in-the-same-server/3535 "2023-02-06T16:43:58Z")
**Posts on this page:** 1
**Showing post:** 37

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### Author: ![erik.sundvall](https://discourse.openehr.org/user_avatar/discourse.openehr.org/erik.sundvall/32/1961_2.png) [@erik.sundvall](https://discourse.openehr.org/u/erik.sundvall)
#### Post date: [21 February 2023 16:55 UTC](https://discourse.openehr.org/t/ehrs-with-different-system-id-in-the-same-server/3535/37 "2023-02-21T16:55:57Z")

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Perhaps we should use/start a separate thread for the discussion about a top ‘SYSTEM’ hierarchy level that includes both EHR and Demographic/Registry parts? That thread could also discuss the suitability/problems of using AQL for querying meshes/graphs rather than trees. Perhaps some Archetype-based sytactic sugar on top of [GQL](https://en.wikipedia.org/wiki/Graph_Query_Language) (AGQL?) and sugar-resolving query preprocessing would do the trick…

Is there a suitable thread to continue in or does somebody want to create one?

[Update: In april 2024 GQL was approved as an ISO standard, some info that is not paywalled by ISO can be found in Olof Morra’s Publication [A Semantics of GQL; a New Query Language forProperty Graphs Formalized.pdf](https://github.com/OlofMorra/GQL-parser/blob/main/src/main/resources/report/A%20Semantics%20of%20GQL;%20a%20New%20Query%20Language%20forProperty%20Graphs%20Formalized.pdf) that is part of the site [https://github.com/OlofMorra/GQL-parser](https://github.com/OlofMorra/GQL-parser)]

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