Update child table

Question

create table p (p1 number constraint ppk primary key);
create table f (f1 number constraint ffk references p);
create trigger pt after update on p for each row begin
update f set f1 = :new.p1 where f1 = :old.p1;
end;
insert into p values(1);
insert into p values(2);
insert into p values(3);
insert into f values(1);
insert into f values(2);
insert into f values(3);
commit;
After this when I execute
update p set p1 = p1+1;
I am seeing all the records updated 4 in table f.This is because of the fact that above dml updates multiple rows at once.
My doubt: Is there any way to track which foreign key values have already been updated? Using that suggested way I would like to modify the trigger such that no row is updated twice.
Thanks in advance.

Answer 1

Please find the code which I have tried for the
same...
DROP TABLE f;
DROP TABLE p;
CREATE TABLE p (p1 NUMBER CONSTRAINT ppk PRIMARY
KEY);
CREATE TABLE f (f1 NUMBER CONSTRAINT ffk REFERENCES
p);
INSERT INTO p VALUES(1);
INSERT INTO p VALUES(2);
INSERT INTO p VALUES(3);
INSERT INTO f VALUES(1);
INSERT INTO f VALUES(2);
INSERT INTO f VALUES(3);
DROP TABLE a;
CREATE TABLE a(arowid ROWID);
DROP PACKAGE pkg;
CREATE OR REPLACE PACKAGE pkg IS
frowid ROWID;
END;
CREATE OR REPLACE PROCEDURE load(r ROWID) IS
     v NUMBER(1) :=0;
BEGIN
     SELECT 1
     INTO v
     FROM a
     WHERE arowid=r;
     IF(v=0) THEN
          INSERT INTO a VALUES(r);
          pkg.frowid:=r;
     ELSE
          DBMS_OUTPUT.PUT_LINE(r||' is already updated.');
     END IF;
END;
CREATE TRIGGER ft AFTER UPDATE ON f FOR EACH ROW
BEGIN
     load(:OLD.ROWID);
END;
CREATE TRIGGER pt AFTER UPDATE ON p FOR EACH ROW
BEGIN
     UPDATE     f
     SET      f1 = :NEW.p1
     WHERE      f1 = :OLD.p1
     AND      f.ROWID=pkg.frowid;
END;
SQL> update p set p1=p1+1;
update p set p1=p1+1
ERROR at line 1:
ORA-02292: integrity constraint (BI_LEARN.FFK)
violated - child record found
SQL>
Could anyone help me for this.
Thanks in AdvanceThe first logical error is here
     AND      f.ROWID=pkg.frowid;pkg,rowid to this point of time never corresponds to ROWID of table f.
That's why UPDATE in trigger doesn't run and also other actions respectively.
BTW: here
CREATE OR REPLACE PROCEDURE load(r ROWID) IS
     v NUMBER(1) :=0;
BEGIN
     SELECT 1
     INTO v
     FROM a
     WHERE arowid=r;
     IF(v=0) THEN
          INSERT INTO a VALUES(r);
          pkg.frowid:=r;
     ELSE
          DBMS_OUTPUT.PUT_LINE(r||' is already updated.');
     END IF;
END;You get an exception NO_DATA_FOUND, if You haven't a record in table.
Your branch starting with IF v=0 will be never processed ...
Regards
Dmytro