I am trying to create a 1:1 Relationship with an object. Where they will exist in the child object only once to prevent duplication of the same master objects entry in the detail table. Is there a validation rule i can use to do this? or am i forced to use a trigger.
Parent_c.Name, can only exist ONCE in the Child_c, so each Child_c.Parent_r.Name will have a unique value. Is there anyway to achieve this via the validation rules or filter a lookup. Thanks in advance.