mysql select in oop php

Question

i have problem in MYSQL select in OOP PHP. i do not know how to write it correct. my code is:

$sql = "SELECT name_mcategory 
            FROM web_main_category WHERE userid=('".$userid."')";
    $result = mysql_query($sql);
    $e=0;
    $maincat=array ();
    while($data=mysql_fetch_array($result))
    { 
        $maincat[$e]=$data['name_mcategory'];
        $e++;

    } 

how to write it in the OOP? i have tried this but it was not working.

class nweb {
var $userid;
var $mcategory;


function Getmain_category () {

$rs = mysql_query("SELECT name_mcategory 
            FROM web_main_category WHERE userid=$this->userid");
  }
$this->tab=mysql_fetch_object($rs);
}
   }

in the print page

$mcat = new nweb();
$mcat->getmain_category ();
$mcat->mcategory=$this->name_mcategory;

how to get data like a $maincat[$e]=$data['name_mcategory'];

Answer 1

If you want to use OOP, then use an OOP DB Layer like PDO :

class nweb extends PDO {

  public $userid, $mcategory;

  public function __construct($hostname, $dbname, $username, $password) {
    parent::__construct($hostname,$dbname,$username,$password);
  }

  public function getmain_category() {
     return $this->query("SELECT name_mcategory FROM web_main_category WHERE userid = {$this->userid}")->fetch();
  }
}

$mcat = new nweb('hostname', 'dbname', 'username', 'password');
var_dump($mcat->getmain_category());

Note: You add some error handing, see pdo::query .

Answer 2

In OOP we usually make a separate class to handle the database operation . For example Database.php so it executes the query and return the result to Category.php or make Category inherit Database.php. If you want a better way use the PHP Activerecord.

Answer 3

check like this

 class nweb {
   var $userid;
   var $mcategory;


  function getmain_category () {

             $rs = mysql_query("SELECT name_mcategory 
                    FROM web_main_category WHERE userid = {$this->userid}");

             return mysql_fetch_object($rs);
  }

}



//print page


   $mcat = new nweb();
   $data = $mcat->getmain_category ();

   $e=0;
   $maincat=array ();
   while($data=mysql_fetch_array($result))
   { 
        $maincat[$e]=$data['name_mcategory'];
        $e++;
   }