Need help: OOP in PHP

[Anon]

I browsed many php class codes and found all of them messed data storage model/data processing model with data definition.

I think all entity should be defined seperately and then define processing class to control them.

For example,
define one class User as container, and defines some user-related info as member and some simple set/get member functions. Up till here, it's absolutely not dependant on actual data storage model.

Then, say our data ia really stored in MySQL table.
then I define one specific Accessor class to make all operations.
class UserAccessor {
function updateUser() // Accept input from form and then update User table.

So in scripts using User:

$someUser = new User('1'); // 1 is uid
$uid = $someUser->getUid();
$someUserAccessor = new UserAccessor;
$userprofile = $someUserAccessor->loadUserProfile($uid); // a select sql to extract User profile with uid as $uid
$someUser->setUserProfile($userprofile); // $userprofile is one array, result of accessor opration and as input to final set user info
$newuserinfo = $someUser->getProfile();

then $newuserinfo array used in all scripts, say if post in forum, then user info can be exrtacted from this array. And from page to page, I think I can use session_register($newuserinfo) to pass user info.

My question is:
Is my idea really feasibile?
How to implement this data definition / data processing model? I need code example, the more detailed the better.

Also anyone has some detailed OOP in PHP related materials, please email to me ([e-mail]). I find all articles in phpbuiklder and other sites have not touched what I want.

Thanks a lot!

[Anon]

I see nothing that should prevent you from doing what you have outlined.

The closest thing I have worked with:

I once wrote a set of classes which works with data having a tree relationship (a node must have a parent unless it's a root node). The actual tree data could be stored either on the file system (where the directory system already implements a tree relationship) or in a database.

The classes were:

Low-level (storage concerned) classes:
- SQLtree
- FStree

Higher level (data definition):
- TreeNode

Now, since PHP doesn't have multiple inheritance, I did it this way:

The low-level tree classes contained all methods needed for storage. Also, the tree classes contained the two following methods:

getRootNode()
getNodeById(int id)

So if you wanted to work with the database implementation, you'd create a node this way:

$t = new SQLtree('nameOfTree'); // returns an object
// of the TreeNode class
$rn = $t->getRootNode(); // returns an object
// of the TreeNode class
$n = $rn -> createChild(); // returns an object
// of the TreeNode class
$n->setAttribute('surname','Andersen','string');
$n->saveAttributes();

If I had wanted the file-system based implementation of the tree, I'd do it like this:

$t = new FStree('nameOfTree');
$rn = $t->getRoodNode();
$n = rn->createChild();
...

I don't know if this helps.

[Anon]

Damn. My post has some code errors. $t would be an SQLtree or an FStree object, not a node object.

[goghs]

Thanks! You give me some hints!

For me, i think maybe i can define one member variable explicitly in my class:

class User {
var $userID;
var accessor; // <- A UserAccessor object

function getUesrProfile() {
    $accessor->loadUserFromDb($this->userID);
}

}

Or maybe other implementation:

class User {
var $userID;

function getUesrProfile($accessor) {
    $accessor->loadUserFromDb($this->userID);
}

}

Which one is feasible in PHP?
Can I have some member variables as object? If ok, I think maybe i need define then in class and keep all backend operations totally invisible, that is, they are in fact called through member functions.

And another question: can anyone tell me how to use callback function. I feel maybe I need callback functions in class.