Lookup field deletion behaviors
Key Takeaway
When the lookup record is deleted, an optional lookup field can clear its value (the default), block the deletion, or delete the child record too.
A lookup field on a child record points to another record, called the lookup record. When you create an optional lookup relationship field, you decide what happens to the child record if someone deletes the lookup record. The choice matters because it is one of the main ways a lookup relationship differs from a master-detail relationship, where deleting the master always deletes its details.
Choosing the deletion behavior
A lookup relationship links two objects more loosely than a master-detail relationship does. When you create an optional lookup relationship field, you set the "What to do if the lookup record is deleted?" option. You pick one of three behaviors:
- "Clear the value of this field"
- "Don't allow deletion of the lookup record that's part of a lookup relationship"
- "Delete this record also"
These three choices are offered when the lookup field is optional. If you make the lookup field required for saving a record, the field is also required on the page layout. In that case, you can't choose the Clear the value of this field option.