This article seems to be picking on date / time manipulation within PHP. I don't see a database in use.
The title should say something about PHP not handling date/time correctly. This is nothing new.
I'm not positive if MySQL, PostgreSQL, Oracle, or similar would perform the same date and time manipulation correctly. However, I know from personal experience that MySQL handles date/times more consistently than PHP.
I'm curious to see if someone with more knowledge than myself can chime in on the issue.