OK

SELECT *;
FROM Table;
WHERE Field = MainTable.PKField;
INTO ARRAY aTemp

IF _TALLY > 0
RETURN .F.
ELSE
RETURN .T.
ENDIF

The field used in the select will be an indexed field - so is optimized.

If I use the SEEK - I would just

IF SEEK(cValue)
RETURN .T.
ELSE
RETURN .F.
ENDIF

Kev