Posted by LiveFreeAndRoam on 06/25/06 12:16

Hi,

I am on a steep learning curve... I would appreciate your advice on a
design decision regarding class hierachies. (See below)

Especially notice that my Table class creates the DataAccess object.

------------------------------------------------
class DataAccess extends MDB2 {
// DataAccess properties and methods
var $db;
function __construct($dsn) {
$this->db =& MDB2::factory($dsn);
}
}

class Table {
// table properties and methods
var $dao;
function __construct() {
$this->dao = new DataAccess(); // <<< OK?
}
}

class Product extends Table {
// Product properties and methods
}
--------------------------------------------------

One issue I have noticed is that when I attempt to recover the Product
Object from the $_SESSION superglobal that the DataAccess object is
unusable. MDB2 complains with:

MDB2 Error: not found: could not find MDB2 instance

OK, I can overcome this error by simply creating a new Product object and
copying the data from the $_SESSION variable into the newly created object.
Though, this seems terribly inefficient. I would have preferred to simply
say:

$product = unserialize($_SESSION['product']);
$product->query($query);

Instead I have to do this:

$sessprod = unserialize($_SESSION['product']);
$product = new Product();
$product->setProperties($sessprod->getPropertiesExcludingDao());
$product->query($query);

Of course, I have considered creating a DataAccess object outside of my
table definition. This would require some tedious changes to the code-base,
since everywhere I create a Table object, I would need to also create a
DataAccess object.

Before I go ahead with changing this, I would really appreciate your input.
Will I be trading one problem for another? Is there a better way to design
this?

Kind regards,
LFaR.

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