Classes

[tsilenzio]

Well I want to use classes and ive used them before in Visual Basic, C++, and Java but not for PHP if I create a class what will keep it alive from page to page (because all variables die from one page load to the next)

[Lumio]

You have to send the variables to another page.

There are differente ways to save a value for another page:

• GET-Variables
  GET-Variables are in the URL... for example: www.example.com?var1=value1&var2=value2
  You can get that variable like that:
  

  echo $_GET['var1'];

  
  

• POST-Variables
  POST-Variables are sent with a form. So you need a form or you send it with Javascript.
  You can get them with
  [/code]$_POST['variable-name'];[/code]
  
• COOKIE-Variables
  Before you can use a cookie, you must set it with for example setcookie. You can use it after a refresh
  
• ...
  There also other types of them... read more
  

[tsilenzio]

yea i know how to use vairables but is there a way to send a whole class in a $_POST or $_SESSION?

[trq]

You could use serialize, though $_SESSION vars get serialized automatically.

 

Personally, Ive never really had the need to try and create persistant objects.

[cmgmyr]

why can't you just re-initiate it?

[per1os]

yea i know how to use vairables but is there a way to send a whole class in a $_POST or $_SESSION?

 

$_SESSION would work, and no need to serialize it as thorpe said.

 

Basically this would work:

<?php
include('class.def.php'); // has to be before session_Start
session_start();

if (!isset($_SESSION['class_name'])) {
       $_SESSION['class_name'] = new class_name();
}else {
   $x=1;
}
$class &= $_SESSION['class_name']; // dunno if keeping the reference works but yea

if ($x==1)
    echo $class->get_var('test');

$class->set_var('test', 'Testing');

$_SESSION['class_name'] = $class;
?>

 

[tsilenzio]

well let me ask this then if i have a class asigned to each user and each class has about 8 - 20 vars in it and there will be a class for each person logged in on each page that needs the information in it (like 90% of all my pages) then when there are about 500 - 4,000 ppl on the page at once will this cause the server to laggg REALLY bad or you dunno or what? I would assume it would but then again im no PHP / MySQL expert

[per1os]

If thats the load you except, I would re-instantiate the object each call. The session is stored in memory and could cause some potential problems.

 

Just generate a function in the class called getUserData or PopulateClass that is called when the constructor is ran and fills the class with needed data.

 

 

EDIT::

You may be fine keeping it in session like I described, but I have no clue. I never implemented that on a huge system with a lot of people.

[tsilenzio]

ok good idea but would it slow up server load laot if it initalized the data for every var in each class from the tables in MySQL? or not really  I know that ODBC Databases r slow on my PC so i assumed evvery database is slow like that =/ not sure if mySQL is like lightning fast compared to it..

[per1os]

Most servers database are really fast, you should really be only running 1 query to get all the data. Multiple queries, where 1 would suffice is what drags ya down.

 

But MySQL is very efficient and fast if configured properly and in 3NF form.