DECLARE
n NUMBER;
BEGIN
n := 0;
FOR i IN
(
SELECT s.*
FROM sourse_table s
WHERE NOT existx (SELECT 1 FROM destination_table d WHERE d.column_key = s.column_key )
)
LOOP
n:= n+1;
INSERT INTO destination_table d VALUES (s....);
IF n>=100 THEN
COMMIT;
DBMS_OUTPUT.put_line('...');
n := 0;
END IF;
END LOOP;
COMMIT;
END;