How Duplicate Check Works
If you have more than one field marked as Duplicate Check, the system will check for identical information in both fields. That means that the information will have to be identical in both fields for the system to find a duplicate.
Having too few or too many duplicate check fields may create challenges. Two or three are usually sufficient.
In the above example, both the "Name" and the "Social Security Number" fields have been marked as Duplicate Check. Two people with the same name can be entered into the system, as long as they have different social security numbers. It seems logical that people who have different SSNs would be two different individuals, even if they happened to have the same name. Should there actually be two different people with the same name and SSN, the record could be saved only if something is altered, such as a middle name or initial.
If we were to keep adding more Duplicate Check fields, we might increase our risk for creating duplicate records. If we added an address field to our form as a third duplicate check, for example, and our client moved to a new address - someone might enter them into the system thinking they were new, when really only their address had changed. In that case, the Duplicate Check would only find duplicate records if the data in *all three* fields were identical to something that had already been entered.
Administrators set a field as "duplicate check" in field properties. (see article "Standard Properties for Fields")