use active records in library

Hello,
i'm writing my personal library for Users.
but i have a problem trying to query my db.
is wrong call db from Lib?

PHP Code:

Class User
{
    public function __construct(){
       
    }
    
   
    
    public function userExists($id){
        $query = $this->db->get_where('users', array('id' => $id));
        $number = $query->num_rows();
        if($number > 0)
            return true;
        else
            return false;
    }
        

} 


obviously in my controller i loaded the lib with 

PHP Code:

$this->load->library('user'); 


the error is

Code:

A PHP Error was encountered

Severity: Notice

Message: Undefined property: User::$db

Filename: libraries/User.php

Line Number: 28

Backtrace:

File: /web/htdocs/www.mysite.com/home/API/application/libraries/User.php
Line: 28
Function: _error_handler

File: /web/htdocs/www.mysite.com/home/API/application/controllers/User_authentication.php
Line: 29
Function: userExists

File: /web/htdocs/www.mysite.com/home/API/index.php
Line: 315
Function: require_once


Fatal error: Call to a member function get_where() on a non-object in /web/htdocs/www.mysite.com/home/API/application/libraries/User.php on line 28
A PHP Error was encountered

Severity: Error

Message: Call to a member function get_where() on a non-object

Filename: libraries/User.php

Line Number: 28

Backtrace:

is a good way?

Libraries are a little different in they don't have immediate access to the `$this` super global.

There's a couple ways to do it but here's how most will tell you to...

PHP Code:

public function __construct()
    {
        $ci = &get_instance();
    } 


Then, anywhere you use '$this->' use '$ci->' instead,

for example:

PHP Code:

public function userExists($id){
        $query = $ci->db->get_where('users', array('id' => $id));
        $number = $query->num_rows();
        if($number > 0)
            return true;
        else
            return false;
    } 


Enliven Applications - Open Blog is now Pubvana - CI4 Tutorials

Here is a template for creating a Custom Library.

PHP Code:

class Custom_Library {

    /**
     * Class variables - public, private, protected and static.
     * --------------------------------------------------------------------
     */

    /**
     * @var
     * CI Super Object.
     *
     * Example: $this->CI->Library->Method();
     */
    private $CI;

    /**
     * @var
     * array ( $index => array ( $key => $val ));
     */
    protected static $reg = array(array());

    /**
     * __construct ()
     * --------------------------------------------------------------------
     *
     * Constructor    PHP 5+
     *
     * NOTE: Not needed if not setting values or extending a Class.
     *
     */
    public function __construct()
    {
        $this->CI =& get_instance();

        log_message('debug', "Custom_Library Class Initialized");
    }

} 


What did you Try? What did you Get? What did you Expect?

Joined CodeIgniter Community 2009.  ( Skype: insitfx )

PHP Code:

public function userExists($id){
        $query = $ci->db->get_where('users', array('id' => $id));
        $number = $query->num_rows();
        if($number > 0)
            return true;
        else
            return false;
    } 


Thanks guys.. the only correction i've done is row number 2

PHP Code:

$query = $ci->db->get_where('users', array('id' => $id)); 


i corrected it as

PHP Code:

$query = $this->ci->db->get_where('users', array('id' => $id)); 


Now it works. Rep+ for enlivenapp and InsiteFx

Also just a note:

It's called Query Builder now not Active Records.

What did you Try? What did you Get? What did you Expect?

Joined CodeIgniter Community 2009.  ( Skype: insitfx )