Is It Possible to Utilize Velocity to Detect Attribute Change/Edit?

[ArmstKP]

I was wondering if it is possible to utilize ArcGIS Velocity to detect an attribute change/edit, to trigger another action, like sending a text message or email?  Has anybody done this?

[ArmstKP]

@PeterNasuti Thank you for the context of the issue.  I have reached out to @JeffEismanGIS via DM. 

[brudo]

Thanks @PeterNasuti, but is that true? I just tested the expression "First(TrackFieldWindow('fieldName', -1,0))" within the Velocity UI in a random RTA, and it evaluates to null as expected, without raising an error. Are you sure the fix you mentioned was not snuck into the current release after all? I did not actually try to run it.

On the other hand, I would expect positive values to always fail in an RTA, and only work in a BDA, since it is processing the current incoming record and has not yet seen the future records at the time of evaluation... 

[brudo]

@ArmstKP that makes sense - so it seems the Track function is forgivingly clipping its result to the available range and returning an empty array when called for the first feature; but the index into the resulting zero-length array is raising that error. In that case you could use "if (Count(trackResult) > 0)" interchangeably with checking the TrackIndex up front. Or alternatively, you could just call "First(TrackFieldWindow(...))" instead of "TrackFieldWindow(...)[0]", which will then return null for an empty array. And to be sure, there are other ways as well.

[PeterNasuti]

@brudo We had a call with @JeffEismanGIS and @ArmstKP to implement the workaround for the frontend limitation at the current 3.3 release. As soon as 4.1 goes live in late February this limitation will no longer be present.

You are correct that in real-time analytics positive values are not valid for backend evaluation, but they are valid for big data analytics. At the current release we do not have a way to insert that nuance to the Arcade expression evaluation but we are considering validation inspection options for future releases.

Expect more examples, conference demos, and community videos from the real-time time moving forward on the use of track functions highlighting use cases and configurations. In the meantime feel free to log a support case or direct message a Velocity team member for assistance with the workaround for this negative value specification at the current release.

[ArmstKP]

@JeffEismanGIS Do you know if the updates have gone through for this as of yet? 

I have followed your example in the last few days and the expression/calculate field for "DidDriverNameChange_String" boolean type.  I have changed the field names in the expression to represent my test source layer and it tests successfully, but it will error out at this expression/calculate field tool when running the BDA...

[JeffEismanGIS]

@ArmstKP Thanks for the follow up, what is the error you are getting when you run the Big data analytic.

[JeffEismanGIS]

@ArmstKP Your welcome

Good Luck