Unique value based on two fields having the same value
Is there a method in which you can prevent a record being duplicated based on the value of two fields being the same. In other words, if a records is added and the value of "Field_One" and "Field_Two" are the same as a previous record, the record can not be added. If one is differant, then record will be added.
In the database "Field_One" is mandatory and "Field_Two" is not and can be left blank.
If have thought of creating a calculated field combining both fields and making this new field unique, "Field_One" has a value entered and "Field_Two" is yet to be entered and therefore empty, it can clash with another record.
Therefore it needs to be some sort of script triggered after the second field has been decided....or something else?