OOP PHP5 starter

Vbabiy

Hello guys i started to write DB class and though i could maybe get some feedback on it so far. I just started to use OOP a few weeks ago and i am still have a hard time think in the mindset but i think something are starting to clear up for me.

Remember its still in the works...

<?php
//DB Classes
abstract class DB 
{
	protected abstract function connect();
	public abstract function query($query);
	public abstract function close();
	public abstract function selectDB();
}

class Mysql_DB extends DB 
{
	private $host;
	private $user;
	private $pass;
	private $db;

private $dbcx;

private $error = array();

public function __construct($host,$user,$pass,$db)
{
	$this->host = $host;
	$this->user = $user;
	$this->pass = $pass;
	$this->db = $db;

	$this->connect();
}
	protected function connect()
{
	$connect = @mysql_connect($this->host,$this->user,$this->pass);
	if (!$connect) 
	{
		$this->error['Connection'] = 'Connection could not be made at host: '.$this->host.' --- MYSQL ERROR: '.mysql_error($this->dbcx);
		return false;
	} else {
		$this->dbcx = $connect;
		if ($this->selectDB())
		{
			return true;
		}
	}
}
public function selectDB()
{
	$select = @mysql_select_db($this->db,$this->dbcx);
	if (!$select) 
	{
		$this->error['Database'] = 'Database '.$this->db.' doesnt exist --- MYSQL ERROR: '.mysql_error($this->dbcx);
		return false;
	} else {
		return true;
	}
}	
public function query($query)
{
	if (!$result = @mysql_query($query,$this->dbcx)) 
	{
		$this->error['Query'] = 'Error with Query:\''.$query.'\' --- MYSQL ERROR: '.mysql_error($this->dbcx);
		return false;
	} else {
		return $result;				
	}		
}	
public function affectedRows()
{
	return mysql_affected_rows($this->dbcx);
}	
public function characterSet()
{
	return mysql_client_encoding($this->dbcx);
}	

public function dataSeek($row)
{
	if (@mysql_data_seek($this->dbcx,$row)) 
	{
		return true;
	} else {
		$this->error['DataSeek'] = 'Failure moving pointer to row '.$row.' --- MYSQL ERROR: '.mysql_error($this->dbcx);
		return false;
	}
}
public function setResultType($type)
{
	$this->Result_Type = $type;
}
public function fetchArray($results,$result_type = 'ASSOC')
{
	switch ($result_type)
	{
		case 'ASSOC':
			$result_type = MYSQL_ASSOC;
			break;
		case 'NUM':
			$result_type = MYSQL_NUM;
			break;
		case 'BOTH':
			$result_type = MYSQL_BOTH;
			break;
		default:
			$result_type = MYSQL_ASSOC;
			break;
	}

	$returnArray =@mysql_fetch_array($results,$result_type);
	if ($returnArray) 
	{
		return $returnArray;
	} else {
		$this->error['FetchArray'] = 'Unable to fetch array --- MYSQL ERROR: '.mysql_error($this->dbcx);
		return false;
	}
}
public function close()
{
	if (@mysql_close($this->dbcx)) 
	{
		return true;
	} else {
		$this->error['Close DB'] = $this->host.'Failed to close --- MYSQL ERROR:'.mysql_error($this->dbcx);
		return false;
	}
}
public function isError()
{
	if (empty($this->error)) 
	{
		return false;
	} else {
		return true;
	}
}
public function getError()
{
	$errors ='';
	foreach ($this->error as $cause => $error) 
	{
		$errors .= $cause.' ~~ '.$error.'<br />';
	}
	return $errors;
}
public function __destruct()
{
	$this->close();
}
}
?>

halojoy

Have you tested basic function of your class?
does it work like you thought it would?

I suppose it is working alright. Looks good.
You did a very good homework on Class and objects in PHP.

As I by now probably know LESS than you do,
I wont make any code critics.
At least not until I eventually have run your code practically
and got all them BUGS and Problems we didnt predict in theory.
🙂

Vbabiy

From what i have test everything works as excepted 🙂

halojoy

did you simulate errors
to see if error reports is okay?

for example.
- disable MySQL program - and run connect
- try to select a non-existent database
- try bad user, bad pass .... unauthorisized use
- ....

.. I think you get it

Vbabiy

Yeah i have done that it all seemed good... The only one problem is i start kinda getting in to the OO mentally and then it seem to go away and i feel lost in my code again....LOL... i am having the hardest time switching from procedural to OOP... I have read some many articles and ready two books at the time... i hope the OOP thinking kicks in soon.

Vbabiy

This is where i have my problem, i will describe my situation and hopefully some one can help me from here.

My Situation:
I have a idea for a Classified Ad System and i want to build it in OOP, but my problem is i am not sure what should i divide in to class.

This is what i got going through my head since its going to be a Classified Ad system i should have abstract class AD which will be the interface for all extending Ad class, such as CarAd, Boat Ad, Home Ad etc... For the Ad class i think i a have the right idea. But from there on i am not sure what else should classes.

I don't know maybe i got this all screwed up i would like to hear from anyone for some insight on my problem.

halojoy

that sounds okay
a class is good mainly when dealing with one specific kind of objects/operations

I almost never use Classes, myself
and if i can avoid it, i dont use functions() either
.. because it makes script slower and to get any major advantage
you would have to use same advanced long function/class 2 times or more
in same script execution

there is nothing you cant do as good or better

with use of normal code or functions

Class on the other hand, is practical
if you want to write many different aplications that are in same category.
Class is a way to re-use code, and do not have to write same sub script again.

Class - Object programming
it is really only a bunch of functions that deals with same sort of things
and can share
....same variables, data

....and same subroutines

Usually all php applications need an user interface
.... user submits data, usually <FORM>
.... user gets results .. output, most often as a Display

so you could add a Form Class, for input
and a template Class .. a Page class, for output
-------------------

there are many such Form and Templates classes around
for free download

I am not a member at http://www.phpclasses.org/
but I often endup there when searching google for some class application

Right now for example http://www.phpclasses.org/browse/
has got classes in category: Templates(110)
and I am sure has got even more Form Classes than 110

laserlight

.. because it makes script slower and to get any major advantage
you would have to use same advanced long function/class 2 times or more
in same script execution

Actually, I would say that the rule is "if you have to write it twice, scowl but write it; if you have to write it thrice, it is time to reach for a function". Of course, this only applies to relatively short pieces of code. For a long piece of code, you may want to place it in a function even if it is used only once, simply to improve code readability.