Class B needs class A, how to reference it properlly ?

ftrudeau

Greetings all
Here's the context.

I've got a class, lets call it class A, which was build to include various methods for MsSQL. Class 'B' needs class 'A', to parse data returned from MsSQL queries, and to manipulate them.

In my current code, im am doing this :

$a = new A;
$b = new B;

and in the constructor of class B :

function B()
{
global $a;

$this->a = $a;
}

This works fine, but is this the right thing to do ?

Thanks.

marian

you should be looking at oop on php.net to find exactly what you want; below is the link.

http://us2.php.net/manual/en/keyword.extends.php

goodluck!

ahundiak

One nice thing about programming is that there is no "right" way to do things. It all depends.

In PHP 4
$this->a = $a;

Creates a copy of $a. This may or may not be what you want. In PHP 5 a copy is not made. So if you rely on there being a copy made then your app might fail on under PHP 5. Consider using:
$this->a =& $a;

Do you really need to store $a inside of the B object? If not then consider just adding global $a to whatever methods actually need access to $a.

Finally, does it make sense to pass $a as an argument to the B class constructor?
function b(&$a) {
$this->a =& $a;

That gets rid of the global dependency and allows creating B objects with different $a links. On the other hand, it means that each time you do create a B object then you have to have $a handy.

It all depends.