The setup is straightforward but the maintenance is real. Pair with Validation Rules to enforce at the platform level, document the dependency matrix as part of object documentation, and audit when picklist values change.
- Confirm Controlling and Dependent fields exist as picklists
Both fields must exist before the dependency can be created. Create the picklists with their full value sets first.
- Open Field Dependencies for the object
Object Manager, pick the object, Fields and Relationships, Field Dependencies. Click New.
- Pick the Controlling Field and Dependent Field
Controlling is the field whose value drives the dependency. Dependent is the field whose available values change based on the Controlling value.
- Map the dependency matrix
Start with Include All to enable every combination, then disable specific invalid cells. The starting-empty pattern is slower for large picklists.
- Save and test in the UI
Open a record of the object, pick a Controlling value, confirm the Dependent picklist refreshes correctly. Test multiple Controlling values to verify the matrix.
- Add a Validation Rule for API-level enforcement
Field Dependencies enforce in the UI only. A Validation Rule that asserts the same logic at the platform level holds the dependency across Data Loader and API entry paths.
- Document the dependency in object documentation
The matrix is not self-explanatory to anyone who did not configure it. Document the rationale so future admins do not have to reverse-engineer.
Picklist or checkbox whose value drives the dependency.
Picklist whose available values change based on the Controlling value.
Per-cell configuration of which Dependent values are available for each Controlling value.
Platform-level enforcement that complements the UI-level dependency. Required for API-entry integrity.
Dependent fields can themselves control deeper Dependent fields. Adds matrix complexity per level.
- Field Dependencies enforce in the UI only. Data Loader and API can bypass them without a paired Validation Rule.
- The dependency matrix starts empty by default. Without Include All, no Dependent values appear; admins regularly miss this on first setup.
- Multi-level dependencies multiply matrix configuration burden. Cap at two levels unless absolutely required.
- Record Type picklist restrictions interact with Field Dependencies. Both apply simultaneously; reasoning about combined behavior takes practice.
- Picklists past a few hundred values per axis become unwieldy. Consider lookup relationships or grouped picklists for genuinely large value sets.