Does the TranslateBrowsePath operate only at first level of the reference? It is possible to achieve // like in xpath?|OPC UA Implementation: Stacks, Tools, and Samples|Forum|OPC Foundation

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Does the TranslateBrowsePath operate only at first level of the reference? It is possible to achieve // like in xpath?
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Rudolf Pribis
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03/27/2023 - 00:22
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Dear all,

maybe it is a silly question, but is the TranslateBrowsePath capable of doing of doing something like the XML xpath (e.g. bookstore//book Selects all book elements that are descendant of the bookstore element, no matter where they are under the bookstore element)?

if not, what is the proposed way of doing something like that?

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Randy Armstrong
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03/27/2023 - 06:55
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No. The main reason is an OPC UA Server is not an XML document or an OO database that can be easily searched with complex queries. In many cases, following references requires multiple subsystems to be interrogated to find out what information is currently present.  With some servers, loading all possible nodes to resolve those types of queries is not technically viable.

In the future, some OPC UA servers will support a service based on GQL: https://www.gqlstandards.org/w.....l-standard

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Rudolf Pribis
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03/27/2023 - 11:56
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Randy Armstrong said
No. The main reason is an OPC UA Server is not an XML document or an OO database that can be easily searched with complex queries. In many cases, following references requires multiple subsystems to be interrogated to find out what information is currently present.  With some servers, loading all possible nodes to resolve those types of queries is not technically viable.

In the future, some OPC UA servers will support a service based on GQL: https://www.gqlstandards.org/w.....l-standard

  

Thanks for the prompt clarification.

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