Trying to learn OOP php

[wolf73]

Hi I have a question regarding following code, which i got from a turorial

********** varaiable.php ************

<?
$GLOBALS['db_host'] = "host"
$GLOBALS['db_user'] = "user"
$GLOBALS['db_pass'] = "pass"
$GLOBALS['db'] = "db"
?>


********* classphp.php ******************

include "variable.php"

<?
class db_qur
{

function db_qur() {
$this->db_host = $GLOBALS['db_host'];
$this->db_user = $GLOBALS['db_user'];
$this->db_pass = $GLOBALS['db_pass'];
$this->db = $GLOBALS['db'];

$GLOBALS['connection'] = mysql_connect($this->db_host, $this->db_user, $this->db_pass)
or die( "Unable to connect to SQL server");
mysql_select_db($this->db)
or die( "Unable to select database");
}
}
?>

why are we doing

$this->db_host = $GLOBALS['db_host'];

why don't just
db_host = $GLOBALS['db_host'];

Isn't the purpose of doing
$this->db_host = $GLOBALS['db_host'];

so that variable can accessed with out being passed to the function. But here we are passing the varaibles any way

$GLOBALS['connection'] = mysql_connect($this->db_host, $this->db_user, $this->db_pass)

so what the point doing
$this->db_host = $GLOBALS['db_host'];

Thanks

 

[sleipnir214]

There are variables declared at the class-level and variables that are declared at the method level.

A method-level variable will be "$foo" and only exists as long as the method is running. The class-level variable "$this->foo" exists so long as the class is instantiated as an object.

A more canonical example might be something like:

<?php
class foo ()
{
   var $foo;

   function foo ($bar)
   {
      $this->foo = $bar;
   }
}

Want the best answers? Ask the best questions! TANSTAAFL!

 

[sleipnir214]

This also becomes more important with the object model in PHP 5.x, which adds variable visibility:

http://www.php.net/manual/en/language.oop5.visibility.php

Want the best answers? Ask the best questions! TANSTAAFL!

 

[wolf73]

thanks for your example. I am little confused.

You said $foo is method level but it is declared outside the method, shouldn't it be inside the function.

I have other question I will ask later