This is the same scope question as the previous entry — the inventory has the same point asked two ways. The answer is the same: workflow field updates can only write to the triggering record itself or to the master record of a master-detail relationship.
Re-stating the limits
| Target | Allowed? |
|---|---|
| Triggering record | Yes |
| Master of a master-detail relationship | Yes |
| Parent of a lookup relationship | No |
| Child records | No |
| Sibling records | No |
| Unrelated records | No |
Why the question gets asked twice
In real interviews, this pair often shows up as a one-two punch:
- First the interviewer asks the general version: “Can a workflow field update touch related-object fields?”
- Then a follow-up to pin you down: “Can it update lookup parents or only master-detail?”
The right answer to both is master-detail only.
Flow is the modern answer
For any cross-object update that isn’t master-detail-parent, the 2026 recommendation is Record-Triggered Flow:
- Use a Get Records to retrieve related records (lookup parent, children, anything)
- Use an Update Records to write back
- Use Run Asynchronously if the related records are managed by other automation and you want to avoid recursion
What about formula fields as a workaround?
You can sometimes avoid the need for a field update entirely:
- A cross-object formula can surface a parent’s value live on the child — no write needed
- A roll-up summary field can aggregate child values on a master-detail parent
- An Apex trigger can write anywhere, with the trade-off of code
What interviewers want
- The same answer as the previous question — stay consistent, don’t accidentally change the story
- Acknowledge the duplication if the interviewer seems to be testing whether you’ll contradict yourself
- Point to Flow as the modern fix when workflow’s scope is too narrow
Verified against: Salesforce Help — Field Updates. Last reviewed 2026-05-17 for Spring ‘26 release.