The Mysql module is an obsolete interface and you should not use it in new code. Source.
that was on the tutorial , just google for more info
This is the danger of just copying and pasting random crap off the web. CPAN (which I linked to above) always has the latest versions of modules and has the documentation straight from the authors. Why would you grab a random tutorial when the subject matter experts, the guys who wrote the module have the latest and greatest right in the docs?