okay so I'm still figuring out classes

I read this tutorial which sort of explained it http://www.phpbuilder.com/columns/rod19990601.php3

But I still don't know really when or why to use them.

I know how to do everything on here www.w3schools.com/php/default.asp

So say I was making a log in system for a website, when / what would I use classes for. Could someone just give me examples of the class name / description and when you would use it? I don't need actual code, I know how to program, just not why / when to use them.

classes are best when you need "re-usable" code, and if know how, why or when to use OOP methods and properties you know how to use classes.
All that a class does, is encapsulate methods (sub routines and functions) and properties (constants or variables) into a "wrapper" with a name.

One use is if you are writing an application that can use different database servers, you could encapsulate all the MySQL code in one class, Access in another, MSSQL in a third class etc.
Then your app could check a configuration parameter and include the appropriate class/module.

All the property and method names are the same across all three classes, but the code will have the appropriate syntax for the DB server.

Originally Posted by chrishirst

classes are best when you need "re-usable" code, and if know how, why or when to use OOP methods and properties you know how to use classes.
All that a class does, is encapsulate methods (sub routines and functions) and properties (constants or variables) into a "wrapper" with a name.

One use is if you are writing an application that can use different database servers, you could encapsulate all the MySQL code in one class, Access in another, MSSQL in a third class etc.
Then your app could check a configuration parameter and include the appropriate class/module.

All the property and method names are the same across all three classes, but the code will have the appropriate syntax for the DB server.

Well say my site is just adding / reading a database, would I ever use classes?

There are no specific circumstances in PHP where you must or even should use OOP.

Originally Posted by Skeddles

Well say my site is just adding / reading a database, would I ever use classes?

You could. You might have a database class that handles all of your queries.

I usually use classes if I'm making something for somebody else, or if I'm building something massive that is hard to keep track of. However, I usually just write procedural code, as long as it's not repeated.

Seeing as you're making a site that will connect and read to a DB, you probably don't need a class. The same effect could be accomplished with a few lines of code:
1) connect to DB
2) read DB
3) echo contents of result-set