Question

I have following table structure

ID  Name  Parent_ID

1   abc   0

2   efg   1

3   hij   1

4   klm   2

5   nop   3

and so on….id is generated in a sequence

I want a PL/SQL to coy this same data in same table but id should be generated by seq and Parent_ID should be mapped accordingly…that means..after PL/SQL it should look like

ID  Name  Parent_ID

1   abc   0

2   efg   1

3   hij   1

4   klm   2

5   nop   3

6   abc   0

7   efg   6

8   hij   6

9   klm   7

10  nop   8

can any1 help me in this…thnx

Answer 1

So, here is your original data:

SQL> select * from t23
  2  /

        ID NAM  PARENT_ID
---------- --- ----------
         1 abc          0
         2 efg          1
         3 hij          1
         4 klm          2
         5 nop          3

SQL>

This procedure populates a PL/SQL collection with the extant rows. It loops through those rows, populating an associative array with a new ID which is indexed by the original ID. (Note the assignment uses the 11g syntax for getting a sequence value, rather than the traditional selecting from DUAL). The ID is then chnaged to the new value, and the PARENT_ID is updated with the value stored in the associative array. Lastly the new rows are inserted into the table using the bulk FORALL syntax,

SQL> declare
  2      type num_lookup is table of pls_integer
  3          index by pls_integer;
  4      id_translate num_lookup;
  5
  6      type t23_nt is table of t23%rowtype;
  7      new_rows t23_nt;
  8  begin
  9      select *
 10      bulk collect into new_rows
 11      from t23
 12      order by id asc;
 13
 14      for i in new_rows.first()..new_rows.last()
 15      loop
 16          id_translate(new_rows(i).id) := s23.nextval;
 17          new_rows(i).id := s23.currval;
 18          if new_rows(i).parent_id != 0
 19          then
 20              new_rows(i).parent_id := id_translate(new_rows(i).parent_id);
 21          end if;
 22      end loop;
 23
 24      forall j in new_rows.first()..new_rows.last()
 25          insert into t23 values new_rows(j);
 26
 27  end;
 28  /

PL/SQL procedure successfully completed.

SQL> 

And, lo!

SQL> select * from t23;

        ID NAM  PARENT_ID
---------- --- ----------
         1 abc          0
         2 efg          1
         3 hij          1
         4 klm          2
         5 nop          3
         6 abc          0
         7 efg          6
         8 hij          6
         9 klm          7
        10 nop          8

10 rows selected.

SQL>