topic Attribute rule for maintaining many-to-many relationships in Attribute Rules Questions

Attribute rule for maintaining many-to-many relationships

CarstenAndersson — Fri, 20 Mar 2026 12:39:54 GMT

I have two polygon feature classes, Municipality and District. There is a many-to-many relationship between the two, and therefore an intermediate table called Municipality_District_Rel. The relationships are automatically handled with attribute rules, based on a municipality must overlap a district with 80% or more for them to be related. And if a municipality cover less than 80% percent, the relationship has to be deleted.

The Arcade expression is:

// Arrays to store edits var edits = []; var adds = []; var deletes = []; // Get all District features var allDistricts = FeatureSetByName($datastore, "District"); // Find District features that intersect this Municipality feature var intersectingDistricts = Intersects(allDistricts, $feature); // Determine which District features that this Municipality overlaps with 80% or more var overlappingDistrictGlobalIds = []; for (var district in intersectingDistricts) { var districtGeometry = Geometry(district); var districtArea = Area(districtGeometry); var intersectionGeometry = Intersection(Geometry($feature), districtGeometry); var intersectionArea = Area(intersectionGeometry); if ((intersectionArea / districtArea) >= 0.8) { // This district overlaps, so store the GlobalID for it Push(overlappingDistrictGlobalIds, district.GlobalID); } } // Determine which relationships to add (new District features that overlaps with at least 80%) var relatedDistricts = FeatureSetByRelationshipName($feature, "Municipality_District_Rel", ["GlobalID"]); for (var index in overlappingDistrictGlobalIds) { var districtGlobalId = overlappingDistrictGlobalIds[index]; Console(districtGlobalId); var relatedDistrict = First(Filter(relatedDistricts, "GlobalID = '" + districtGlobalId + "'")); if (relatedDistrict == null) { // A relationship didn't exist, so add it Push(adds, { 'attributes': { 'Municipality_GlobalID': $feature.GlobalID, 'District_GlobalID': districtGlobalId } }); } } // Get existing relationships between Municipality and District features var allRelationships = FeatureSetByName($datastore, "Municipality_District_Rel", ["*"]); var relationships = Filter(allRelationships, "Municipality_GlobalID = '" + $feature.GlobalID + "'"); // Determine which relationships to delete (no longer overlapping with at least 80%) for (var relationship in relationships) { if (!Includes(overlappingDistrictGlobalIds, relationship.District_GlobalID)) { // No longer overlapping enough, so delete the relationship Push(deletes, {'GlobalID': relationship.GlobalID}); } } // Return edits dictionary if there are changes to the relatio if (Count(adds) > 0 || Count(deletes) > 0) { Push(edits, { 'className': "Municipality_District_Rel", 'adds': adds, 'deletes': deletes }); return {'edit': edits}; }

When I click Analyze I get:

But when I try to save the attribute rule I get this:

What am I doing wrong?

Re: Attribute rule for maintaining many-to-many relationships

MikeMillerGIS — Fri, 20 Mar 2026 12:55:52 GMT

Try this, my only guess is that adds or deletes is an empty array and maybe that is causing an issue

// Arrays to store edits var edits = []; var adds = []; var deletes = []; // Get all District features var allDistricts = FeatureSetByName($datastore, "District"); // Find District features that intersect this Municipality feature var intersectingDistricts = Intersects(allDistricts, $feature); // Determine which District features that this Municipality overlaps with 80% or more var overlappingDistrictGlobalIds = []; for (var district in intersectingDistricts) { var districtGeometry = Geometry(district); var districtArea = Area(districtGeometry); var intersectionGeometry = Intersection(Geometry($feature), districtGeometry); var intersectionArea = Area(intersectionGeometry); if ((intersectionArea / districtArea) >= 0.8) { // This district overlaps, so store the GlobalID for it Push(overlappingDistrictGlobalIds, district.GlobalID); } } // Determine which relationships to add (new District features that overlaps with at least 80%) var relatedDistricts = FeatureSetByRelationshipName($feature, "Municipality_District_Rel", ["GlobalID"]); for (var index in overlappingDistrictGlobalIds) { var districtGlobalId = overlappingDistrictGlobalIds[index]; Console(districtGlobalId); var relatedDistrict = First(Filter(relatedDistricts, "GlobalID = @districtGlobalId")); if (relatedDistrict == null) { // A relationship didn't exist, so add it Push(adds, { 'attributes': { 'Municipality_GlobalID': $feature.GlobalID, 'District_GlobalID': districtGlobalId } }); } } // Get existing relationships between Municipality and District features var allRelationships = FeatureSetByName($datastore, "Municipality_District_Rel", ["*"]); var relationships = Filter(allRelationships, "Municipality_GlobalID = '" + $feature.GlobalID + "'"); // Determine which relationships to delete (no longer overlapping with at least 80%) for (var relationship in relationships) { if (!Includes(overlappingDistrictGlobalIds, relationship.District_GlobalID)) { // No longer overlapping enough, so delete the relationship Push(deletes, {'GlobalID': relationship.GlobalID}); } } // Return edits dictionary if there are changes to the relatio if (Count(adds) == 0 && Count(deletes) == 0) { return; } var edit_payload = { 'className': "Municipality_District_Rel", } if (Count(adds)){ edit_payload['adds'] = adds } if (Count(deletes)){ edit_payload['deletes'] = deletes } Push(edits, edit_payload); return { 'edit': edits };

Re: Attribute rule for maintaining many-to-many relationships

CarstenAndersson — Mon, 23 Mar 2026 05:34:26 GMT

Thanks Mike,

but unfortunately I get the same error. My initial though was a version issue. I am using ArcGIS Pro 3.3, but I get the same error message on ArcGIS 3.5.

The line that causes the error is: var allRelationships = FeatureSetByName($datastore, "Municipality_District_Rel", ["*"]);

But, it's the only way I can think of to delete the existing relationships.

Could this be a bug?

Re: Attribute rule for maintaining many-to-many relationships

MikeMillerGIS — Tue, 24 Mar 2026 13:50:01 GMT

Could be, I never tried to work with a M:N in arcade.