How to convert this piece of sql code to oledb command?

[GaryMazzone]

UPDATE S SET
     S.empnum = ER.Employee_Number
FROM scard S
INNER JOIN Employee_Records ER
   ON s.FirstName = ER.First_Name

BUT What happens when you have 2 people with the same first NAME (John) then you really don't know what you get in the end

[ronelpisan]

UPDATE S SET
     S.empnum = ER.Employee_Number
FROM scard S
INNER JOIN Employee_Records ER
   ON s.FirstName = ER.First_Name

BUT What happens when you have 2 people with the same first NAME (John) then you really don't know what you get in the end

Thank you Gary for responding my concern. Actually it should be done by finding Fullname and Birthday for the exact. FirstName there is just an example. Any idea? I would highly appreciate your ideas and suggestions.