Explain how to fix this fatal error?

[jrws]

Hi guys, me again.

I have a fatal error of

Call to a member function on a non-object

How do you fix these errors?

The specific error that it is saying is about the mysql_num_rows function called Num_Rows; here's the code for it

<?php
function Num_Rows($sql)
    {
        $sql = $this->query($sql);
        $sql = mysql_num_rows($sql) or die(mysql_error());
        return $sql;

    }

?>

And here is a snippit of the code in use (specifically the problem)

<?php 
require_once ('../inc/config.php');
$db = new mysql();
//.......
//This is in a class mind you:
$username_query = "SELECT username FROM user WHERE username = '$username'";
    	$username_queryR = $db->Num_Rows($username_query);
        $email = $this->clean($email);
        $email_query = "SELECT email FROM user WHERE email = '$email'";
        $email_queryR = $db->Num_Rows($email_query);

?>

The question is how do I fix this problem and any future problems such as this?

[ToonMariner]

well you have used the OOP notation with no visible instantiation of an object...

 

you need to pass the dabase obect in too!!!!

 

Why have you wriiten a function to do what a method already available to you can do????

 

Why are you using $this outside a class????

 

what are you doing?

 

 

[jrws]

No idea, I am new to PHP and programing in general, trying random stuff. I know my logic is way off, What do you mean by pass the database object?

edit: The num_rows function is inside a class. And what do you mean by there is already a method?

[ToonMariner]

<?php 
require_once ('../inc/config.php');
$db = new mysql();
//.......
//This is in a class mind you:
$username_query = "SELECT username FROM user WHERE username = '$username'";
$username_queryR = $db->query($username_query);
echo $username_queryR->num_rows;

$email_query = "SELECT email FROM user WHERE email = '$email'";
$email_queryR = $db->query($email_query);
echo $email_queryR->num_rows;

?>

 

what do you mean to achieve with this line? $email = $this->clean($email);

 

answer to question 1.

 

Not being funny but you need to know about scope if you are going to code - even at a basic level....

 

question 2.

 

you should read up on classes and OOP and learn what a 'method' is...

[jrws]

A method is a function no? And the point of cleaning the emai is to prevent unsanitary user input.

[ToonMariner]

A method is a function no?

 

well no not really - in this ocntext a method belongs to an object - something you can perform on that object.  AN object (or an instance of a class) needs to be aware of what it can do - this is done by declaring these methods within the objects template (the class).  Unless you have coded something like

<?php
class Myclass
{
private $foo;

protected function__construct()
{
  $this->foo = 'Initiated';
}

private function bar ()
{
  echo $this->foo;
}
}
?>

 

get some books or read some stuff on PHP OOP and you will pick it up v quickly...

Doubt anyone on here will teach you to code!!!!

 

And the point of cleaning the emai is to prevent unsanitary user input.

 

you need something to clean before you call a 'clean' on it and where is the method 'clean' defined?

 

again this will come...

[jrws]

In the user class. It takes the arguments given, $user, $pass1, $pass2, $email.

It then uses these to perform the rest of the script. I was thinking that the arguments would be from the form users submit, therefore making the $user = $_POST['user'; etc