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Searching for value based on partial string

andrew_Inwood

Searching for an event frame based on Attribute Value is very useful. I am interested in knowing whether it can be used to search on String values, using only partial strings.

 

This article is quite useful:

https://pisquare.osisoft.com/s/Blog-Detail/a8r1I000000Gv9KQAS/coding-tips-for-using-the-afsearch-in-operator?t=1726547940087

 

But in it it explains that the "In" operator is used for searching for a string value that is in a list of pre-defined values. Does this mean that it can't use wildcard or other pattern matching?

 

I tried it in my own sample code, and it didn't work.

AFSearchValueToken textToken = new AFSearchValueToken("|TEXT_ATTRIBUTE", "*Hello*", AFSearchOperator.In);

I can always load all the AFEventFrames (eg. filter by template first), and then find the matching ones using Linq, but I was hoping for a server-side search.

 

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    Hi Andrew,

     

    I was the author of that referenced blog back when I was an OSIsoft employee. One restriction on IN that perhaps wasn't emphasized enough: IN only works with EXACT values, though for strings I think case-insensitive match is okay. So it cannot be used for partial strings or use wildcards.

     

    I would suggest your 2 areas of concern should be: (1) getting the right answer, and (2) getting that answer in a performant way.

     

    One issue with an AFAttributeSearch is that it does require a full load of all base elements into memory. Typically to review attribute values requires a sluggish client-side search.

    Note an event frame is a base element. The good news is that if your event frames are closed, i.e. have a EndTIme set, then with captured values you could possibly have the search occur server-side. But again, it is the partial strings that will cause performance issues.

     

     

  • 0 in reply to Rick_Davin_3.0

    ​ 

     

    Would the "TEXT_ATTRIBUTE" example AFAttribute be a static AFAttribure or is it a PIPoint?

     

    Another consideration: is there any possible way to have some minor re-design. You have one AFAttribute string containing (or better yet) starting with given text. Can you split this into 2 AFAttributes: 1 for general categorization, and the 2nd for specific subcategory?

     

    Or consider using an Hierarchical AFEnumerationSet ?

    https://docs.aveva.com/bundle/pi-server-f-af-pse/page/1021919.html

     

    Example:

    100 = Hello

    110 = Hello|Admin

    120 = Hello|Manager

    130 = Hello|Engineer

    140 = Hello|Operator

     

    Now you could search on the numeric Value of the enumeration as being >= 100 and < 200.

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