How to update primary key column

Question

Hi,
Can you suggest me best workaround/algorithm for below task:
(Oracle 10g, Solaris OS.)
Situation:
Table P has primary key column "Code", child tables F1, F2, ..., F15 reference with foreign key column "P_Code" column "P.Code", and we don't know which of the child tables has data for particular "P.Code" value.
Task:
Change "P.Code" value from 100 to 200. So that result would be that record P[Code = 100] should be updated as:
update P set
Code = 200
where Code = 100;And child tables column "P_Code" should be updated as:
update F1, F2, .., F15 set
P_code = 200
where P_code = 100;The best solution would be that one very easily can repeat that task.
Edited by: CharlesRoos on 28.12.2010 12:10

Answer 1

If you are looking for reusable and repetitive solution, then may be...
SQL> CREATE TABLE p (p_code NUMBER PRIMARY KEY);
Table created.
SQL> INSERT INTO p VALUES(100);
1 row created.
SQL> INSERT INTO p VALUES(300);
1 row created.
SQL> INSERT INTO p VALUES(500);
1 row created.
SQL> commit;
Commit complete.
SQL> CREATE TABLE F1 (p_code NUMBER REFERENCES p(p_code));
Table created.
SQL> CREATE TABLE F2 (p_code NUMBER REFERENCES p(p_code));
Table created.
SQL> CREATE TABLE F3 (p_code NUMBER REFERENCES p(p_code));
Table created.
SQL> INSERT INTO F1 VALUES(100);
1 row created.
SQL> INSERT INTO F3 VALUES(100);
1 row created.
SQL> INSERT INTO F2 VALUES(500);
1 row created.
SQL> commit;
Commit complete.
SQL> CREATE OR REPLACE PROCEDURE update_child_parent(pi_p_code_old NUMBER,
  2                                                  pi_p_code_new NUMBER) IS
  3    CURSOR table_to_update IS
  4      SELECT table_name,
  5             to_number(extractvalue(xmltype(DBMS_XMLGEN.getxml('SELECT count(*) c FROM ' ||
  6                                                               table_name ||
  7                                                               ' WHERE p_code=' ||
  8                                                               pi_p_code_old)),
  9                                    '/ROWSET/ROW/C')) cnt
10        FROM user_tables
11       WHERE table_name IN ('F1', 'F2', 'F3');
12 
13  BEGIN
14    EXECUTE IMMEDIATE 'ALTER TABLE p DISABLE PRIMARY KEY CASCADE';
15    UPDATE p SET p_code = pi_p_code_new WHERE p_code = pi_p_code_old;
16    FOR i IN table_to_update LOOP
17      IF i.cnt > 0 THEN
18        EXECUTE IMMEDIATE 'UPDATE ' || i.table_name || ' SET p_code=' ||
19                          pi_p_code_new || ' WHERE p_code=' || pi_p_code_old;
20      END IF;
21    END LOOP;
22    EXECUTE IMMEDIATE 'ALTER TABLE p ENABLE VALIDATE PRIMARY KEY';
23  END update_child_parent;
24  /
Procedure created.
SQL> EXECUTE update_child_parent(100,200);
PL/SQL procedure successfully completed.
SQL> SELECT * FROM p;
    P_CODE
       200
       300
       500
SQL> SELECT * FROM F1;
    P_CODE
       200
SQL> SELECT * FROM F2;
    P_CODE
       500
SQL> SELECT * FROM F3;
    P_CODE
       200
SQL> INSERT INTO p VALUES(300);
INSERT INTO p VALUES(300)
ERROR at line 1:
ORA-00001: unique constraint (HR.SYS_C005931) violated
SQL> EXECUTE update_child_parent(500,900);
PL/SQL procedure successfully completed.
SQL> SELECT * FROM p;
    P_CODE
       200
       300
       900
SQL>  SELECT * FROM F2;
    P_CODE
       900
SQL>