Need help in writing a tricky sql/PL/Sql Procedure

Question

Hi,
I have a Branch table with just two fields in it node1 and Node2, The table looks like this
node1 | node2
-------|---------
1 | 2
3 | 2
3 | 4
4 | 5
1 | 5
1 | 6
5 | 6
in the above data if you draw lines between node_1 and node_2 you will see that there are 3 different paths to get from 1 to 5, as follows
/--------6-------\
1----------------------5
\2------3-------4/
Now I need to Find all the nodes between 1 and 5 or all the possible paths from node 1 to node 5 in this case I have 3 possible paths they are as follows
1-2-3-4-5
1-3-5
1-5
Now I know if this data was stored in a hierarchical manner I can get the results i want by using CONNECT BY and SYS_CONNECT_BY_PATH.
Is there a way to transform this data into a hierarchcal manner so that I can use the CONNECT BY or can somebody give me an Idea as to how to write a PL/SQL procedure to get the result I want.
Any help will be greatly appreciated

Answer 1

Hi!
1.Create another table Branch1 to hold 'transformed data'.
2.Use the following procedure to insert data into branch1 table.
declare
cursor n is select * from branch;
begin
for nrec in n loop
if nrec.node1 = 5 then
     insert into branch1(node1,node2) values(nrec.node2,nrec.node1);
elsif nrec.node2= 5 then
     insert into branch1(node1,node2) values(nrec.node1,nrec.node2);
else
if      nrec.node2> 5      then
     insert into branch1(node1,node2) values(nrec.node1,nrec.node2);
elsif nrec.node1> 5 then
     insert into branch1(node1,node2) values(nrec.node2,nrec.node1);
elsif (nrec.node1 < nrec.node2 ) then
     insert into branch1(node1,node2) values(nrec.node1,nrec.node2);
else
     insert into branch1(node1,node2) values(nrec.node2,nrec.node1);
end if;
end if;
end loop;
commit;
end;
3.Then execute the following connect by query:
SQL> select lpad(' ',level*2,' ')||node1 from branch1
2 start with node1=1
3 connect by prior node2=node1;
Hope this is satisfactory.
Thanks!