Hierarchical update

Question

Hi Everybody,
Problem,
I have to update the parent node such that the sequence number of the parent is always greater than child.
(Assuming all the old(above) nodes obeys this condition)
My main logic is to get the difference between min (child_sequence_number) and the new sequence number .Add 1 to that difference.
Add the value to all the above that new sequence number .
value = P_EMP_GROUP_SORT_NBR - MIN_EMP_GROUP_SORT_NBR ) + 1Help me to write efficient procedure.
My problem is as shown.
create or replace procedure EMP_GROUP_SEQ_NUM_UPD (
   P_EMP_GROUP_SORT_NBR   in   number
  ,P_EMP_GROUP_ID         in   number
as
   V_EMP_GROUP_SORT_DIFF number;
   V_MIN_SORT_NMBR number;
begin
   select ( P_EMP_GROUP_SORT_NBR - MIN_EMP_GROUP_SORT_NBR ) + 1
   into   V_SORT_DIFF
   from   ( select    min ( GP.EMP_GROUP_SORT_NBR ) MIN_EMP_GROUP_SORT_NBR
           from       EMP_GROUP_DTL DT join EMP_GROUP GP
                      on ( DT.EMP_GROUP_ = GP.EMP_GROUP_ )
           start with DT.TAIL_EMP_GROUP_ = P_EMP_GROUP_
           connect by prior DT.EMP_GROUP_ = DT.TAIL_EMP_GROUP_ );
   update EMP_GROUP
   set EMP_GROUP_SORT_NBR = EMP_GROUP_SORT_NBR + V_SORT_DIFF
   where  EMP_GROUP_ in ( select    GP.EMP_GROUP_
                         from       EMP_GROUP_DTL DT join EMP_GROUP GP
                                    on ( DT.EMP_GROUP_ = GP.EMP_GROUP_ )
                         start with DT.TAIL_EMP_GROUP_ = 1002
                         connect by prior DT.EMP_GROUP_ = DT.TAIL_EMP_GROUP_ );
exception
   when others
   then
      dbms_output.PUT_LINE ( 'Error in procedure EMP_GROUP_SEQ_NUM_UPD' );
      dbms_output.PUT_LINE ( sqlerrm );
      raise;
end EMP_GROUP_SEQ_NUM_UPD;
/Sample Data For the EMP_GROUP_DTL is shown
PGRP_ID     RGMN_GRP_SORT_NBR
1001      9901
1002     9902
1003      9903
1004      9904
1005      9905
1006      9906
1007      9907
1008      9908
1009      9909
1010      9910
1011      9911
1012      9913
SAMPLE DATA FOR EMP_GRP
GRP_ID     GRP_ID
1011 1009
1009     1001
1009     1006
1008     1007
1008     1004
1008     1005
1004     1002
1011     1008
1008     1003
It can help to get level and emp_grp_id and emp_grp_srt_nbr
select  level
      , DT.GRP_ID
      , GP.GRP_SORT_NBR
from    emp_GRP_DTL DT
       join
       emp_GRP gp
       on (DT.emp_GRP_ID = gp.emp_GRP_ID)
start with DT.TAIL_emp_GRP_ID = 1002
connect by prior DT.emp_GRP_ID = DT.TAIL_emp_GRP_ID

Answer 1

Hi,
Sorry, I'm not sure I understand the question.
Whenever you ask a question, please post a little sample data (CREATE TABLE and INSERT statements) so people can re-create your problem and test their solutions. If you can ask a question about commonly available tables, such as those in the scott schema, then you don't have to post any sample data.
Also post the results you want from the data you posted. If you're doing a DML operation (such as UPDATE) the results will be the state of the changed table after the DML.
The results of a CONNECT BY query are in the order you want (parents always come before their children), and ROWNUM will reflect that order.
Consider the following example from the scott.emp table:
SELECT     empno
,     mgr
,     LPAD (' ', 2 * (LEVEL - 1)) || ename     AS name
,     LEVEL                         AS lvl
,     ROWNUM                         AS rwnm
FROM     scott.emp
START WITH     mgr     IS NULL
CONNECT BY     mgr     = PRIOR empno
.    EMPNO        MGR NAME                    LVL       RWNM
      7839            KING                      1          1
      7566       7839   JONES                   2          2
      7788       7566     SCOTT                 3          3
      7876       7788       ADAMS               4          4
      7902       7566     FORD                  3          5
      7369       7902       SMITH               4          6
      7698       7839   BLAKE                   2          7
      7499       7698     ALLEN                 3          8
      7521       7698     WARD                  3          9
      7654       7698     MARTIN                3         10
      7844       7698     TURNER                3         11
      7900       7698     JAMES                 3         12
      7782       7839   CLARK                   2         13
      7934       7782     MILLER                3         14You can use CONNECT BY and ROWNUM in the USING clause of a MERGE statement.