Oracle ROWID property
(Oracle only) This is where you specify whether the records retrieved by the selected Query object should be referenced by means of their ROWIDs. If not, for example because the table is an RDBMS view, you can set this property to No.
Also, you must set this property to No if you have changed the underlying query to something like:
SELECT DISTINCT <non-key column>
Otherwise the DISTINCT clause will apply to the (implicitly used) ROWID instead of the non-key column. The "same" data might then appear to be displayed more than once.