PHP - using extend in classes

[saturnprods]

Hi Guys,

I've always included a small php file with the connection and then written classes that make a query and handle the return data.

This time, I am trying a different approach.

I created a class for the database connection and am using EXTEND for subsequent classes.

For example, I have:

class dao{
  function connect_db(){
    //connector function
  }

  function query($sql){
     $this->query = mysql_query($sql);
     return $this->query;
   }

}

class website extends dao{
    function getUsers(){
     //get user function
   }
}

My question is how do I run the dao->query function from within the getUsers function?

Would it be something like:

function getUsers(){
 $result = parent::query("select * from tbl_user");
 while($r = mysql_fetch_assoc($result)){
  echo $r["user_name"].'<br />';
}
}

or can I just call it as if it were in the same class:

function getUsers(){
 $result =$this->query("select * from tbl_user");
 while($r = mysql_fetch_assoc($result)){
  echo $r["user_name"].'<br />';
}
}

Still trying to get a hang of classes and such. Thanks for you patience and help.

[NogDog]

Hi Guys,
...or can I just call it as if it were in the same class...

Yes (as long as you did not declare the method to be "private" in the parent class).

[NogDog]

PS: Note that the MySQLi and PDO database extensions are already object-oriented, so you could simply(?) use them instead of creating your own OO implementation of the old MySQL extension.

[saturnprods]

ps: Note that the mysqli and pdo database extensions are already object-oriented, so you could simply(?) use them instead of creating your own oo implementation of the old mysql extension.

you mean i've been reinventing fire and the wheel???

:d

thanks a million. I don't know how i missed this....[turns red]

[NogDog]

you mean i've been reinventing fire and the wheel???

:d

thanks a million. I don't know how i missed this....[turns red]

Probably because the MySQLi extension came out with PHP5, but there is an awful lot of legacy PHP4- code out there using the older MySQL extension, and even new code that feels a need to be PHP4-compatible (even though it's been close to a year now since PHP4 has ceased being supported in any way).

[saturnprods]

NogDog, this has worked great. Thanks for your help.

But is it possible to write classes that extend this mysqli class?

[NogDog]

NogDog, this has worked great. Thanks for your help.

But is it possible to write classes that extend this mysqli class?

Yes, for instance:

class Foo extends mysqli
{
   public function __construct($host, $user, $password, $db)
   {
      parent::__construct($host, $user, $password, $db);
   }

   public function bar()
   {
      echo "This is my new method added to the mysqli class";
   }
} 

But it all depends on what you actually need to do: perhaps it makes more sense to pass a MySQLi object to another class, for instance.

class Foo
{
   private $db;

   public function __construct(MySQLi $db)
   {
      $this->db = $db;
   }

   public function bar($id)
   {
      $stmt = $this->db->prepare("SELECT * FROM `table` WHERE `id` = ?");
      $stmt->bind_param('i', $id);
      // and so forth...
   }
}

$db = new MySQLi('localhost', 'user', 'password', 'database');
$foo = new Foo($db);
$foo->bar();