DECLARE
   TYPE tt_type IS TABLE OF table_name.no%TYPE
      INDEX BY BINARY_INTEGER;

   tt_type_no   tt_type;
   rec_count           NUMBER;
BEGIN

   SELECT     LEVEL
   BULK COLLECT INTO tt_type_no
         FROM DUAL
   CONNECT BY LEVEL <= 999999;

   FORALL rec_count IN tt_type_no.FIRST .. tt_type_no.LAST
      INSERT INTO table_name
                  (no, checkin_date
                  )
           VALUES (tt_type_no (rec_count), SYSDATE
                  );
   COMMIT;
END;

SQL> create table test (id number, datum date);

Table created.

SQL> set timing on
SQL> insert into test (id, datum)
  2    select level, sysdate
  3    from dual
  4    connect by level < 999999;

999998 rows created.

Elapsed: 00:00:03.84
SQL>

 insert /*+ APPEND */ into test (id, datum)
      select level, sysdate
      from dual
      connect by level <= 999999;