[SOLVED] Quick OOP question

[Flames]

I recently learned OOP and then made a DB class to handle connections etc, and there is a public variable called $con which is true if the database is connected.

I have another class which extends my DB class but I seem to be having problems with accessing the $con variable to see if it is connected, how can I do this, I tried using DB::$con but that gave "Fatal error: Access to undeclared static property: Database::$con"

 

Thanks

 

 

[anupamsaha]

I recently learned OOP and then made a DB class to handle connections etc, and there is a public variable called $con which is true if the database is connected.

I have another class which extends my DB class but I seem to be having problems with accessing the $con variable to see if it is connected, how can I do this, I tried using DB::$con but that gave "Fatal error: Access to undeclared static property: Database::$con"

 

Thanks

 

Do this:

 

public static $conn;

 

Does this help?

 

[Flames]

The error has gone but it still isnt getting the right value, it should have the value true but it is saying it is false

[anupamsaha]

The error has gone but it still isnt getting the right value, it should have the value true but it is saying it is false

 

Please post the DB class here.

 

[Flames]

class Database
{

private $db_host = ''; 
private $db_user = ''; 
private $db_pass = ''; 
private $db_name = ''; 
public static $con;

public function connect()
    {
        if(!$this->con)
        {
            $myconn = @mysql_connect($this->db_host,$this->db_user,$this->db_pass);
            if($myconn)
            {
                $seldb = @mysql_select_db($this->db_name,$myconn);
                if($seldb)
                {
                    $this->con = true; 
                    return true; 
                } else
                {
                    return false; 
                }
            } else
            {
                return false; 
            }
        } else
        {
            return true; 
        }
    }

public function disconnect()
{
	if($this->con)
	{
		if(@mysql_close())
		{
			 $this->con = false; 
			 return true; 
		}
		else
		{
			 return false; 
		}
	}
}	
  }

 

class Login extends Database
{
public function checkDatabase($field, $check)
{
if(Database::$con)
{
 $query = "SELECT * FROM Users where $field = '$check'";
 $result = mysql_query($query) or die("error");;
 if(mysql_num_rows($result)>0)
	{
	 return "no";
	}
	else
	{
	 return "yes";
	}
}
else
{
return "not connected";
}
}
}

[anupamsaha]

I see the db informations (the private variables) are blank in the class. How are setting those? Directly in the class? If not, create a constructor in the class to set those and then use those in the connect() method. As they are blank in the class, you get "false" from the connect() method.

 

<?php
/**
* Database.php
*/
class Database
{

private $db_host = ''; 
private $db_user = ''; 
private $db_pass = ''; 
private $db_name = ''; 
public static $con;

/**
* Magic construct method
*/
public function __construct($host, $user, $password, $dbname) {
  $this->$db_host = $host;
  $this->db_user = $user;
  $this->db_pass = $password;
  $this->db_name = $dbname;
}

public function connect()
    {
        if(!$this->con)
        {
            $myconn = @mysql_connect($this->db_host,$this->db_user,$this->db_pass);
            if($myconn)
            {
                $seldb = @mysql_select_db($this->db_name,$myconn);
                if($seldb)
                {
                    $this->con = true; 
                    return true; 
                } else
                {
                    return false; 
                }
            } else
            {
                return false; 
            }
        } else
        {
            return true; 
        }
    }

public function disconnect()
{
	if($this->con)
	{
		if(@mysql_close())
		{
			 $this->con = false; 
			 return true; 
		}
		else
		{
			 return false; 
		}
	}
}	
  }
?>

 

To call this class:

 

<?php
/**
* dbtest.php
*/
include('Database.php');
$db = new Database('localhost', 'username', 'password', 'database_name');
var_dump($db->connect());
?>

 

[jxrd]

parent::$con;

[Andy-H]

/* Add to database class... */
protected function isConnected()
{
   return $this->con;
}

/* Login Class */

class Login extends Database
{
public function checkDatabase($field, $check)
 {
 if(parent::isConnected())

 

[Flames]

It still returns not connected but there are no errors now

[Andy-H]

$login = new Login('localhost', 'user', 'pass', 'dbName');

print_r($login);

 

What does that return?

[Flames]

Login Object ( [db_host:private] => XXXXXXX [db_user:private] => XXXXXXX [db_pass:private] => XXXXXXX[db_name:private] => XXXXXXX[con] => )

[Andy-H]

Have you tried calling the checkDatabase method yet?

 

Also I dont see any use in creating a static variable without assigning a value.

[Ken2k7]

Well, for one, your DB connect method is not written correctly.

 

By the way, you can connect without selecting a DB. Not sure of your logic there.

public function connect()
    {
        if(!self::$con)
        {
            $myconn = @mysql_connect($this->db_host,$this->db_user,$this->db_pass);
            if($myconn)
            {
                $seldb = @mysql_select_db($this->db_name,$myconn);
                if($seldb)
                {
                    self::$con = true;
                    return true; 
                }
            }
            self::$con = false;
            return false;
        } else
        {
            return true; 
        }
    }

 

After you did that, replace

if(Database::$con)

 

With

if(parent::connect())

 

Since your DB connect method returns a boolean, you can just do that instead of accessing member data publicly. This way, you can set the $con var in DB to private.

[Flames]

thanks for the help guys