Fatal error: Call to a member function query() on a non-object,$mysql->query($query)

Question

samsons17 -4 Posting Whiz in Training

15 Years Ago

HI,..i've been working on this simple project that i need to submit it tomorrow.
I really in rushing a little bit.

But while i working on this oop project, my program give the strange little fatal error about my query which is this

Fatal error: Call to a member function query() on a non-object in C:\xampp\htdocs\listnote\index.php on line 25

I really sure that i wrote everything down correctly already, so that i really dont understand why did this error appear :(

Below here are the code :

This is my database class which i name it db.php

?php
//my database class
class Db {

    // make sure we dont connnect database to every function
    public $mysql;

    function __contruct(){
        $this->mysql = new mysqli('localhost','root','password','db') or die ("problem");
    }
?>

and here is my main program, index.php

<div id="todo">
                  <?php
                  require 'db.php';
                  $db = new Db();
                  $query = "SELECT*FROM list";
                  $results = $mysql->query($query);

                  if($results->num_rows){
                      while($row = $results->fetch_object()) {
                          $title = $row->title;
                          $description = $row->description;
                          $id = $row->id;

                          //the rest of the code go here
                 
                  }
                  ?>
</div>

could anyone figure it out for me?i really desperate right now as i could not continue my work because of this just small error.

Thanks in advance.

mysql object-oriented-programming php

Edited 15 Years Ago by samsons17 because: n/a

2 Contributors
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Latest Post 15 Years Ago Latest Post by aquilax

Dani AI

Generated 11 Months Ago

That fatal error means you are calling a method on a variable that is not an object (usually null or undefined). In this thread there are two common causes: a typo in the constructor name prevents the connection from being created (__construct must be spelled exactly), and using a variable that does not exist in scope (e.g., $mysql->query(...) instead of referencing the connection on your $db instance). To surface the root cause faster, enable strict MySQLi reporting and PHP errors early: mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT); error_reporting(E_ALL); ini_set('display_errors', 1); See mysqli driver report modes and error_reporting.

A small, safer pattern is to keep the connection private and expose a method that runs queries. This guards against accidental use of an uninitialized property and makes error handling consistent.

class Db {
    private $conn;
    public function __construct($host, $user, $pass, $db) {
        mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
        $this->conn = new mysqli($host, $user, $pass, $db);
        $this->conn->set_charset('utf8mb4');
    }
    public function query($sql) {
        return $this->conn->query($sql);
    }
}

Quick checklist: ensure __construct is spelled correctly (docs), the MySQLi extension is loaded (phpinfo), credentials are valid, and you reference the connection via your $db instance. For long-term maintainability consider prepared statements or PDO (PDO manual) and avoid die() in library code.

All 16 Replies

aquilax 7 Junior Poster in Training

15 Years Ago

Test with this code:

<?php
//my database class
class Db {

    // make sure we dont connnect database to every function
    public $mysql;

    function __contruct(){
        $this->mysql = new mysqli('localhost','root','password','db');
        if (mysqli_connect_error()) {
            die('Connect Error (' . mysqli_connect_errno() . ') '
                    . mysqli_connect_error());
        }
    }
}


$db = new DB();
var_dump($db->mysql);
?>

aquilax 7 Junior Poster in Training

15 Years Ago

Yup:

The mysqli extension allows you to access the functionality provided by MySQL 4.1 and above.

http://www.php.net/manual/en/intro.mysqli.php

I think you can use the mysql extension in php 3.0 :

http://www.php.net/manual/en/book.mysql.php

aquilax 7 Junior Poster in Training

15 Years Ago

Check if you have the mysqli module installed (with phpinfo()) also check if you can actually connect to mysql with the given user/pass/database.

aquilax 7 Junior Poster in Training

15 Years Ago

Check my last comment.

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samsons17 -4 Posting Whiz in Training · Answer 1 · 2011-07-26T14:37:09+00:00

Test with this code:

<?php
//my database class
class Db {

    // make sure we dont connnect database to every function
    public $mysql;

    function __contruct(){
        $this->mysql = new mysqli('localhost','root','password','db');
        if (mysqli_connect_error()) {
            die('Connect Error (' . mysqli_connect_errno() . ') '
                    . mysqli_connect_error());
        }
    }
}


$db = new DB();
var_dump($db->mysql);
?>

hurm...not working also..what change is only the error message which is this:

NULL
Fatal error: Call to a member function query() on a non-object in C:\xampp\htdocs\listnote\index.php on line 25

is this somehow something wrong with my php version?
i am running php version 5.3.0..

samsons17 -4 Posting Whiz in Training · Answer 2 · 2011-07-26T14:40:21+00:00

Test with this code:

<?php
//my database class
class Db {

    // make sure we dont connnect database to every function
    public $mysql;

    function __contruct(){
        $this->mysql = new mysqli('localhost','root','password','db');
        if (mysqli_connect_error()) {
            die('Connect Error (' . mysqli_connect_errno() . ') '
                    . mysqli_connect_error());
        }
    }
}


$db = new DB();
var_dump($db->mysql);
?>

hurm...not working also..what change is only the error message which is this:

NULL
Fatal error: Call to a member function query() on a non-object in C:\xampp\htdocs\listnote\index.php on line 25

is this somehow something wrong with my php version?
i am running php version 5.3.0..

samsons17 -4 Posting Whiz in Training · Answer 3 · 2011-07-26T14:50:44+00:00

Yup:
http://www.php.net/manual/en/intro.mysqli.php
I think you can use the mysql extension in php 3.0 :
http://www.php.net/manual/en/book.mysql.php

em but somehow it is not about my php version or mysql version..
i am running php 5.3.0 and my mysql 5.1.37.

i am pretty sure that this code that i wrote is working just fine by using the php and mysql version lower than i have now.

but if this is not the problem..what else?please help..i really confuse and frustrated right now..

samsons17 -4 Posting Whiz in Training · Answer 4 · 2011-07-26T15:11:57+00:00

Check my last comment.

okies i run the phpinfo() but i dont know where to look

but here is some of the things from my phpinfo() :

MysqlI Support enabled
Client API library version 5.1.37
Active Persistent Links 0
Inactive Persistent Links 0
Active Links 36
Client API header version 5.1.37
MYSQLI_SOCKET MySQL

Directive-----------------------Local Value------Master Value
mysqli.allow_local_infile---------On On
mysqli.allow_persistent-----------On On
mysqli.default_host------ no value no value
mysqli.default_port 3306 3306
mysqli.default_pw no value no value
mysqli.default_socket MySQL MySQL
mysqli.default_user no value no value
mysqli.max_links Unlimited Unlimited
mysqli.max_persistent Unlimited Unlimited
mysqli.reconnect Off Off

is there something wrong?

aquilax 7 Junior Poster in Training · Answer 5 · 2011-07-26T15:13:07+00:00

No you have the extension. Did you try to login to the mysql server ?

samsons17 -4 Posting Whiz in Training · Answer 6 · 2011-07-26T15:39:31+00:00

ya i login to mysql server using the same user and password i wrote for the connection to the db..and everything is okay..

hurm..

samsons17 -4 Posting Whiz in Training · Answer 7 · 2011-07-26T15:50:00+00:00

could anyone try my code onto your computer and find out if the u got the same error?
i wonder if it is just me that having this problem..

aquilax 7 Junior Poster in Training · Answer 8 · 2011-07-26T15:57:17+00:00

aquilax 7 Junior Poster in Training

15 Years Ago

Got it :)

__contrcuct() should be __construct()

samsons17 -4 Posting Whiz in Training · Answer 9 · 2011-07-26T15:59:47+00:00

oh wait actually my code for db.php is like this :

<?php
                  require 'db.php';
                  $db = new Db();
                  $query = "SELECT*FROM list ORDER BY id asc";
                  $results = $db->mysql->query($query);

                  if($results->num_rows){
                      while($row = $results->fetch_object()) {
                          $title = $row->title;
                          $description = $row->description;
                          $id = $row->id;
                         
                          //the rest of the code go here...
                      }
                  }
?>

samsons17 -4 Posting Whiz in Training · Answer 10 · 2011-07-26T16:02:28+00:00

Got it :)
__contrcuct() should be __construct()

hey........thank youuuu so much :D
i didnt realize that one is the problem.. >.<

hoho..must be really careful next time..
thanks again for ur time..

aquilax 7 Junior Poster in Training · Answer 11 · 2011-07-26T16:03:17+00:00

The error is in the db.php class:

<?php
//my database class
class Db {

    // make sure we dont connnect database to every function
    public $mysql;

    function __construct(){
        $this->mysql = new mysqli('localhost','root','password','db') or die ("problem");
    }
?>

aquilax 7 Junior Poster in Training · Answer 12 · 2011-07-26T16:03:38+00:00

aquilax 7 Junior Poster in Training

15 Years Ago

Glad I could help

Fatal error: Call to a member function query() on a non-object,$mysql->query($query)

Dani AI

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