I've never needed to use print so I haven't really looked into the various differences.

As for mysqli or mysql, you might as well get used to coding for mysqli since by default PHP5+ has mysql turned off. The functions work about the same from the average user's point of view but mysqli offers developers many more options. By the way, the "i" stands for "improved extension".

Yes you can store and use URL in your MySQL tables. To get the stored data out, you'll need a PHP script to send commands (queries) to the MySQL server and display or in your case redirect the user to content.

As for what is and isn't in what versions of PHP, I couldn't begin to try and answer that question. There are some many changes and bug fixes in each release that you'd just about have to be one of the developers to keep track. Unfortunately, it is just as difficult to try and tell you what is safe and isn't safe. Nearly any "unsafe" method of programming can be safe if you write the code to compensate for any exploits. Additionally, nearly any "safe" method can be a security risk if you don't take care during coding.

I hate to be so cryptic but for a PHP newbie, it is difficult to learn the differences between safe and unsafe. My suggestion is to ask an advanced PHP user if what you intend to do is safe or not until you get a better understanding.

I hope that this will offer you enough information to guide you on to your next question.

vujsa