Attribute Rule to Update Feature Layer with Related Table Value

[JoeBorgione]

I have created a number of attribute rules that populate a given field from underlying feature layers (thanks to Xander Bakker‌).  Now I would like to update a feature layer attribute from a related table.  In Frequently Asked Questions | ArcGIS for Developers  the question How do I access data from related tables sends you to the Featureset page.  But I don't see anything there regarding a related table.

In a nutshell, I have a feature layer of City polygons that I would like to relate to a table of corresponding three letter city codes.  When I add a new feature (centerline, address point etc) I can update the City name easily, but how would I update that City code from a related table?  I'd like to avoid adding yet another field to the City features.  Both the feature layer and related table will reside in the same $datastore, an enterprise geodatabase.

[HusseinNasser2]

Hey Joe

You can use FeatureSetByRelationshipName to read related records, and you can use DML to update features from other tables. 

This blog might help 

Advanced Attribute Rules – Editing features on another class with attribute rules 

[JoeBorgione]

Thank you Hussein Nasser‌; I missed the FeatureSetByRelationshipName.  I'll check it out.

[MikeMillerGIS]

Also check out - arcade-expressions/UpdateParentFeature.md at master · Esri/arcade-expressions · GitHub 

I did not use FeatureSetByRelationship, but did use a PKey/FKey style lookup

[JoeBorgione]

I ended up going a different route using dictionaries, so for the sake of discussion, here is what I went with:

var cityDict = {"ALTA" : "ALT", "BRIGHTON" : "BRT", "BLUFFDALE" : "BLU", 
                "COTTONWOOD HEIGHTS" : "COT","DRAPER" : "DRA", "HERRIMAN" : "HER", 
                "HOLLADAY" : "HOL","MIDVALE" : "MID", "MILLCREEK" : "MCK", 
                "MURRAY" : "MUR","RIVERTON": "RIV", "SALT LAKE CITY" : "SLC",
                "SALT LAKE COUNTY" : "SCO", "SANDY" : "SAN", "SOUTH JORDAN" : "SJC",
                "SOUTH SALT LAKE" : "SSL", "TAYLORSVILLE" : "TAY", 
                "WEST JORDAN" : "WJC", "WEST VALLEY" : "WVC"}
var townDict ={"COPPERTON" : "COP", "EMIGRATION CANYON" : "EMC",
            "KEARNS" : "KEA", "MAGNA" : "MAG", 
            "UNINCORPORATED" : "SCO", "WHITE CITY" : "WHC"}


var city = $feature.INCMUNI_L  //$feature.INCMUN_R
var town = $feature.UNINCCOM_L //$feature.UNINCCOM_L

if (HasKey(cityDict, city)){
    return cityDict[city];
} else if (HasKey(townDict, town)){
    return uninc[town]
}
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In my area of operations, we have both incorporated cities as well as unincorporated townships. The field  INCMUNI_L has the value of the incorporated municipality on the left side of a centerline while the field UNINCCOM_L has the unincorporated community on the left side of a centerline. I should mention that when adding a new centerline, these attributes are updated with another attribute rule that takes the required info from an underlying polygon feature.

I have two rules, one for the left side of the centerlines feature and one for the right side that update a field called CityCode_L or CItyCode_R respectively using the associated values from the dictionaries.