Using PEAR DB inside another class

[minorgod]

I'm trying to rewrite a non-class based application to interface with FlashMX using PHPObject as an open source alternative to Flash remoting. This means re-implementing some code inside new classes.

I've run in to a problem using my PEAR DB object inside my new classes. My external DB object instance is called $dbh. So inside my class, should I be delcaring $dbh as global inside the class definition or should it be declared global inside the specific function inside the class? I'm just trying to figure out the best way to pass my $dbh object into the class so I can call methods such as $articles=$dbh->getAll($query); Could someone please explain this a bit?

[cliffyman]

I don't think declaring anything as global is good OO practice. I'm not an OO expert but I'd definitely avoid doing that.

One idea I hit on is the idea of using a factory class that will supply a PEAR DB object to each of the classes inside my "package." I create a factory class that has get and set methods for the 5 parts of the PEAR DB connecting string (hosttype, username, password, hostname, database), and then has a few methods to build those properties into a connection string and eventually return a new PEAR DB object.

Then, my factory class has a method like newCategory() (category is a class in my application). It includes the file that holds my category class, creates a new instance of it by passing a PEAR DB object to the Category constructor. Then it returns the instance of that new class.

For instance, here's what that code allows me to do in my app like.

// this should probably be an include on every page of your app since it's a useful 'global' thing to have
require("Factory.php");

$factory = new Factory();
$factory->setHosttype("pgsql");
$factory->setUsername("teds_master");
$factory->setPassword("95hotDAWG");
$factory->setHostname("66.202.79.104");
$factory->setDatabase("tedsonline_com");

// now we have an object ready make other objects

// make a new category object
$category = $factory->newCategory();

I'm new to this approach and would love some input from other users. This seems to make life a little easier but maybe I'm missing some OO concept here. Below is the code for the factory class and Category class.

<?php
class ECommerceFactory
{
	// private properties
	var $hosttype;
	var $username;
	var $password;
	var $hostname;
	var $database;



// null constructor
function ECommerceFactory()
{

}



// sets database properties
function setHosttype($arg)
{
	$this->hosttype = $arg;
}

function setUsername($arg)
{
	$this->username = $arg;
}

function setPassword($arg)
{
	$this->password = $arg;
}

function setHostname($arg)
{
	$this->hostname = $arg;
}

function setDatabase($arg)
{
	$this->database = $arg;
}



// gets database properties
function getHosttype()
{
	return $this->hosttype;
}

function getUsername()
{
	return $this->username;
}

function getPassword()
{
	return $this->password;
}

function getHostname()
{
	return $this->hostname;
}

function getDatabase()
{
	return $this->database;
}


/* returns the valid DB string */
function getDBString()
{
	$string  = $this->getHosttype();
	$string .= "://";
	$string .= $this->getUsername();
	$string .= ":";
	$string .= $this->getPassword();
	$string .= "@";
	$string .= $this->getHostname();
	$string .= "/";
	$string .= $this->getDatabase();

	return $string;
}



function getDBObject()
{
	require_once("DB.php");

	return DB::connect($this->getDBString());
}



/* generates objects */
function newCategory()
{
	require_once("quinlan/ecommerce/Category.php");

	return new Category($this->getDBObject());
}
}

?>

<?php
class Category
{
	// "public" properties
	var $id;

// "private" properties
var $db_connection;

function Category($arg)
{
	$this->db_connection = $arg;
}

// more methods...
}

?>