Unable to Update Relationship Fields in Editable Grid (saveInto error)

Hi Everyone,

I am working on an Editable Grid in Appian where the grid data comes from a Record Type (Employee Request). The record also has a relationship (requestDetails) which contains fields like categoryId, typeId, and referenceNumber.

For normal fields (like department or location) I can update values using saveInto with the local variable and fv!index. However, when I try to update fields that belong to the relationship object, the values are not saved and I receive errors.

Example dropdown:

a!dropdownField(
  label: "Category",
  choiceLabels: local!categoryLabels,
  choiceValues: local!categoryValues,
  value: fv!item.requestDetails.categoryId,
  saveInto: {
    a!save(
      fv!item.requestDetails.categoryId,
      save!value
    )
  }
)

This results in the error:

The save target must be a local variable that does not refresh on every evaluation, a process variable, or a node input...

I understand that fv!item cannot be used as a save target, so I tried updating using local!gridData[fv!index], but updating the relationship fields still does not work correctly.

My Questions:

1. What is the recommended way to update relationship record fields inside an Editable Grid?

2. Should the entire parent row be updated using a!update()?

3. Is there a best practice pattern for handling Record Type relationships in editable grids?

Any guidance or working examples would be greatly appreciated.

Thanks in advance!