If user merger a two contacts...
Contact #1
field ABC = 123
Contact #2
field ABC = 456
If field is blank then OK.
Then need to prevent user from merging.
4 respuestas
No. Validation Rules only apply to a single record and can't be applied across multiple records. The only validation rule you could write would be to prevent changing the field once it is set, but that would also prevent non-merge edits as well.