[Solved] absolute n00b question

ok. i'm upgrading from 17 to 19, and there is an update_to_lastest.php file to run before I alter the files.
Now the first time I updated all the files, i did a mistake with the code and had to copy all my backup files back and start over.
My question is this (and I'm thinking I don't, but I want to be sure) once I ran the update_to_latest.php, I was cool right? I don't have to re-run it when I re-copied all the modified files because it was a change in the DATABASE, not the program files.
Am I correct in this assumption?
Now the first time I updated all the files, i did a mistake with the code and had to copy all my backup files back and start over.
My question is this (and I'm thinking I don't, but I want to be sure) once I ran the update_to_latest.php, I was cool right? I don't have to re-run it when I re-copied all the modified files because it was a change in the DATABASE, not the program files.
Am I correct in this assumption?