SQL want to log values before and after update table

Question

I have a problem here.

DB: oracle 9i

I want to save data changes after I execute UPDATE script on my table, in that log I want to compare old values with new values.

How can i do this.

thanks for helping me :)

Answer 1

write simple trigger, by using :OLD and :NEW you can get the value of both new and old value of the table

 create or replace
 trigger tg_name
  after UPDATE ON table_name
 for each row
 BEGIN
 IF :NEW.column1 = :OLD.column1 THEN
 -- any statement 
 END IF;    
-- you can log the old and new value by inserting into log table's too..
END;