How to change a massive amount of foreign keys?

Question

Hi to all!
I'm a newbie here, and I hope I'll find a solution to my problem...
Well, I have to create a copy of row within the same table, with same values except of primary key. That part is ok. Then, I have to change values of that primary key (from old value, to new value) in all foreign keys which references to that column/primary key in parent table. Let's say that isn't problem too, using system tables and informations about constraints and indexes...
But, tricky part comes. Some of those foreign keys are primary keys for their tables, and there are other foreign keys which references to these primary keys, including a column which is primary key in very first (parent) table. And also, that line of primary key-foreign key can go on...
I don't know how deep to check for those keys. Any help with some piece of code (in PL/SQL)? Also, how to start to change value of that, particular column, in line of primary key-foreign key?

Answer 1

Sounds like you need to add a copy function to your application. This will allow you to create a copy of an existing import/export but each will be unique. This would provide you with the ability to change the import/export and retain the old and new details.
A small example using a header and detail table;
select * from orders;
  ORDER_ID ORDER_DATE
         1 27/05/2010
select * from order_lines;
   LINE_ID   ORDER_ID
         1          1
         2          1
         3          1A function that makes a copy of a certain order;
create or replace function copy_order(p_order_id orders.order_id%type)
  return number is
  l_new_order_id orders.order_id%type;
begin
  select orders_seq.nextval
  into l_new_order_id
  from dual;
  insert into orders
    (order_id, order_date)
    select l_new_order_id, sysdate
    from orders
    where order_id = p_order_id;
  insert into order_lines
    (line_id, order_id)
    select order_lines_seq.nextval, l_new_order_id
    from order_lines
    where order_id = p_order_id;
  return l_new_order_id;
end;
Function createdCall the function with order_id 1;
var n number
exec :n := copy_order(1);
PL/SQL procedure successfully completed
print n
n
2There are now 2 similar orders;
select * from orders;
  ORDER_ID ORDER_DATE
         1 27/05/2010
         2 28/05/2010
select * from order_lines;
   LINE_ID   ORDER_ID
         1          1
         2          1
         3          1
         4          2
         5          2
         6          2
6 rows selectedThe first order can be canceled (using a status column or similar) and the second order can be updated, ie add additional lines, etc. or left as is.