About php classes and my sql problem

Question

Thanks. I would like to let user login , And i try to do it in oop way

Here is the loginPage.php

<html>
<body>
<?php require_once("connection.php");
$instance=new connection("527442_1","chi1234a","foodil_zxq_1");
if (isset($_POST['s'])) {
    $SecIns=new login($_POST['u'],$_POST['p']);
    echo $SecIns->enter();
}
?>
<form name="fm" method="POST" action="show.php">
User Name :<input type="text" name="u">
<br>
Password: <input type="password" name="p">
<br>
<input type="submit" name="s">
</form>
</body>
</html>

Here is the oop code which i fail Warning: mysql_query(): supplied argument is not a valid MySQL-Link resource

<?php

class connection
{var $user;
var $pass;
var $db;

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

function conn(){
$conn=mysql_connect('localhost' , $this->user , $this->pass) or die ("Can't connect server");
mysql_select_db($this->db,$conn) or die ("DB error");
}
}

class login extends connection
{

function __construct($id,$pwd)
{$this->id=$id;
$this->pwd=$pwd;
}

function enter()
{$this->query="SELECT * FROM test WHERE id='".$this->id."' AND pwd='". $this->pwd."';";
$result=mysql_query($this->query,$this->conn) or die ("Error:" . mysql_error());
if (mysql_num_rows($this->result)<1)
return "Not correct user";
else
return "Login success";
}
}
?>

The problem is at the function enter() .Should be the format problem?? But i spend a long time on it . Thanks.

1. `var` and omitting the the visibility modificators (`public`, `protected`, `private`) is PHP4-style. You should learn how to write code in PHP5. 2. `mysql` is outdated for a while and will be marked as deprecated soon. You should use `MYSQLi`, or `PDO` instead. 3. You should _never_ access any `$_POST`-value directly without validating (same for `$_GET` and such). — KingCrunch, Jul 27 '11 at 09:49
This wasn't an answer, that was just a comment about what you should clean up. Did you read the answers below? — KingCrunch, Jul 27 '11 at 10:04

JohnP · Accepted Answer · 2011-07-27T09:59:47.160

3

While it's commendable that you want to add organization to your code, adding the methods into a class doesn't automatically make it OOP. I recommend you read up on the basics and then reorganize your classes.

As for your problem,

$result=mysql_query('$this->query','$this->conn') or die( ..
--------------------------^

Those variables you passed are treated as literal strings because you've quoted them. you need to pass it an actual query and a connection object. Just remove the quotes.

Also, I recommend you look into parametrized queries : http://php.net/manual/en/book.pdo.php

EDIT

Looking at your code further, these tips might improve your code

Use upper case names for your classes. This makes them easier to read.
You're correct in moving your connection to a different class, but your usage is wrong.
Even though you've extended your Login class from your Connection class, you don't instantiate a connection object for use inside your Login class even though you refer to it in your code (e.g. - $this->conn)
Instantiate your connection and pass it as a parameter for your other classes. Don't extend them from the connection.

$conn = new Connection($username, $pass, $host, $db); $login = new Login($conn); $login->doLogin($username, $password);

And have a query() method in your connection, so you can call that method from your other classes.

edited Jul 27 '11 at 09:59

answered Jul 27 '11 at 09:48

JohnP

49,507
13
108
140

$login = new Login($conn); ?? I already have a construtor to assign the user input id and password – mary_lee Jul 27 '11 at 10:07
So, if i use $login = new Login($conn); how to modify the constructor??thanks – mary_lee Jul 27 '11 at 10:07
Either have a method to set the connection, or pass it in with the other parameters. Whatever you choose, standardize it for all of your classes. – JohnP Jul 27 '11 at 10:23
sorry but i don't get it. How to pass the connection string? – mary_lee Jul 28 '11 at 01:55
To be precise, how to modify in class LOGIN?? – mary_lee Jul 28 '11 at 01:56
Missing argument 2 for connection::__construct() – mary_lee Jul 28 '11 at 02:13
Missing argument 3 for connection::__construct() – mary_lee Jul 28 '11 at 02:13
Have a look at this question, it goes into detail about this topic : http://stackoverflow.com/questions/4707053/php-user-class-login-logout-signup – JohnP Jul 28 '11 at 05:12

score 0 · Answer 2 · answered Jul 27 '11 at 09:47

$result=mysql_query('$this->query','$this->conn') or die ("Error:" . mysql_error());

This piece of code does not evaluate to PHP stored variables. If you single-quote something, PHP won't attempt to parse it as if it was a variable. Remove the quotes.

After you do that, your code will fail at connection::conn() since there is no function mysql_conn. There is mysql_connect. And it takes arguments in different order (server is first for example, not 3rd argument).

score 0 · Answer 3 · edited Jul 27 '11 at 09:54

0

Try:

{$query="SELECT * FROM test WHERE id='".$this->id."' AND '".$this->pwd".';";

edited Jul 27 '11 at 09:54

Tim Post

33,371
15
110
174

answered Jul 27 '11 at 09:47

Marcin Zaluski

687
5
10

xkeshav · Answer 4 · 2011-07-27T09:56:53.670

you have missed something ; i write collectively from all answers

1 - mysql_conn() is not a function you have written in function conn() {}
2 - remove ' from $result = mysql_query('$this->query','$this->conn')
3 - you have missed one parameter in mysql statement

    $query="SELECT * FROM test WHERE id='$this->id' AND        '$this->pwd';";
                                                         ^ (here)

4 - assign the query in $this->query instead of just $query

score 0 · Answer 5 · answered Jul 27 '11 at 10:33

you did not passed the connection object to the login object , thats why you have this error : Warning: mysql_query(): supplied argument is not a valid MySQL-Link resource . from where the login object is calling the $db , you are using resources in the login class without initiating them ... they are not exist until you set them .

About php classes and my sql problem

5 Answers5