PHP and OOP

lowspeed

I've been trying to dive into OOP with php but i'm a little confused.

In a C++ for example if you create an object it will stay with you throughout the program if you do not drop it.

in php however if your out of the script and lets say call a different page that still uses that class the objects in theprevious script are destroyed.

So what is the purpose ? how is it different then just using functions ?

😕

planetsim

Ok I am assuming you mean execute another script. e.g.

going from index.php to example.php, and not including the file.

Ok well OOP works similar to that of C++ ok not exactly but the basic idea is the same. For example, say we open a C++ Program up and close it, all the objects are destroyed (well not straight away they still exist for some period of time until the memory they occupy is required again), PHP works the same way. You execute a script once its executed passing things over to another script requires some way of the client (browser) to retain the values. Cookies and Sessions come to mind.

Now if we were including files, to PHP once the files have been included its just 1 file being executed instead of 2 or 3 etc, so once the script has executed thats it nothing is going to pass on to another file.

Hope this sort of gives you the idea of what is happening.

lowspeed

Originally posted by planetsim
Ok I am assuming you mean execute another script. e.g.

going from index.php to example.php, and not including the file.

Ok well OOP works similar to that of C++ ok not exactly but the basic idea is the same. For example, say we open a C++ Program up and close it, all the objects are destroyed (well not straight away they still exist for some period of time until the memory they occupy is required again), PHP works the same way. You execute a script once its executed passing things over to another script requires some way of the client (browser) to retain the values. Cookies and Sessions come to mind.

Now if we were including files, to PHP once the files have been included its just 1 file being executed instead of 2 or 3 etc, so once the script has executed thats it nothing is going to pass on to another file.

Hope this sort of gives you the idea of what is happening.

This means i have to stay within one script. which is possible .

But let me ask you this.... lets say i use the same php file for a submit form ...

after the submission it basiclly uses the same php file. but its calling it again from scratch ... there's no retention of object info.

Or am i wrong about this?

planetsim

Yes your correct basically once the PHP file is displayed execution has already finished. You may find this link a little better with the explaination (Client/Server Diagram) http://www.iterrasoft.com/ClientServer.htm

rehfeld

planetsim mentioned it but ill say it again.

you can use sessions to make the data persist from one page request to the next. you can store an object into a session.

lowspeed

Originally posted by rehfeld
planetsim mentioned it but ill say it again.

you can use sessions to make the data persist from one page request to the next. you can store an object into a session.

So lets say you have this

$myObject = new MyClass;

$_SESSION['object'] = $myObject;

how do i retrieve that info ?

Or are we talking about indevidual variables within the object that need to be saved.

thorpe

you might want to take a look at serialize() and unserialize().

mrfritz379

Originally posted by lowspeed
So lets say you have this

$myObject = new MyClass;

$_SESSION['object'] = $myObject;

thorpe's right. you want to use serialize() and unserialize().
So basicially, you'd be transforming the above to:

$myObject = new MyClass; 
$_SESSION['object'] = serialize($myObject);

Then, on the next page of your script you'd start of with:

$myObject = unserialize($_SESSION['object']);

Installer

I'll just interject here with the reminder that PHP isn't an object-oriented language, it's a language with some OOP features.