I'm on Chapter 7 of PHP and MySQL: Novice to Ninja and have successfully set up an admin page that allows me to delete entries in my database tables. I've noticed that when I delete an entry and then an add a new one that the id for the old entry is skipped and the numbering resumes after the skip or skips. For example:

1
2
4
5

Where 3 was the id of a deleted entry. Is this something that will be covered later in the book or is it even an issue to be concerned about?