SQL & PL/SQL

Hi friends,

Any1 can guide me, how to debug oracle PL/SQL package, and have to fix bugs or changing the requirement by using toad, sometimes i resolve the problem, and i take backup in notepad, after sometime if i use the same notepad contents, the something changed, i dont no how to keep the "IF loop" correctly, Sometimes while editing, the loop nevigation changes, so that i am getting more confusions. I dont no how to correct the packages already written, and how to solve problems, i use anonymous for seeing output. Dont no how to identify and fix the bug or requirement changes,. I am not sure where the code need changes. How to test properly for fixing the bugs, and how to change the logic, any1 help me out from this,... kindly give me good solution.. thnak you in advance