How to pass connection varible in other php document

Question

Help me with this code: I get this error.

Notice: Undefined variable: dbCon in C:\xampp\htdocs\Project\core\functions\general.php on line 5

Warning: mysqli_real_escape_string() expects parameter 1 to be mysqli, null given in C:\xampp\htdocs\Project\core\functions\general.php on line 5

Notice: Undefined variable: dbCon in C:\xampp\htdocs\Project\core\functions\Users.php on line 5

Warning: mysqli_query() expects parameter 1 to be mysqli, null given in C:\xampp\htdocs\Project\core\functions\Users.php on line 5

Fatal error: Uncaught Error: Call to undefined function mysqli_result() in C:\xampp\htdocs\Project\core\functions\Users.php:8 Stack trace: #0 C:\xampp\htdocs\Project\login.php(4): user_exists(NULL) #1 {main} thrown in C:\xampp\htdocs\Project\core\functions\Users.php on line 8

Main folder(name -> PHP) has Index.php:

    <?php 
include 'core/init.php';
include 'includes/overall/header.php';
?>

PHP folder has Login.php:

 <?php
include 'core/init.php';

if(user_exists('sudin') === true)
{
    echo 'exists';
}
?>

under php/core folder init.php:

<?php
session_start();

require 'database/connect.php';
require 'functions/general.php';
require 'functions/users.php';
?>

under php/core/database connect.php:

<?php
$dbCon=mysqli_connect('localhost','root','','project_point');

?>

under php/core/functions Users.php:

<?php
function user_exists($username)
{
    $username = sanitize($username);
    $query = mysqli_query($dbCon,"SELECT COUNT('Login_ID')FROM 'login' WHERE 'Username' = '$username'");
    return(mysqli_result($query,0)==1) ? true : false;
}
 ?>

under php/core/functions general.php:

<?php

function sanitize($data)
{
    return mysqli_real_escape_string($dbCon,$data);
}
?>[enter image description here][1]

Sorry for the messy way, here is the treeview:

Thankful for the help

Thanks, that worked. What about the last error (Fatal error)..? — Sudin, Mar 23 '16 at 20:33

Funk Forty Niner · Accepted Answer · 2016-03-23T20:36:20.383

2

There are a few things wrong here.

Firstly, you have a variable scope issue and you're also using the wrong identifier qualifiers in your query being regular quotes:

So, remove the quotes for this:

SELECT COUNT('Login_ID')FROM 'login' WHERE 'Username'
             ^        ^      ^     ^       ^        ^ Remove those

or use ticks:

SELECT COUNT(`Login_ID`) FROM `login` WHERE `Username`

Checking for errors on it using mysqli_error($dbCon) http://php.net/manual/en/mysqli.error.php would have thrown you something about it once it would have fired.

Make your connection global in your user_exists() function

global $dbCon;

Read up on both:

Identifier qualifiers http://dev.mysql.com/doc/en/identifier-qualifiers.html
Variable scope http://php.net/manual/en/language.variables.scope.php

edited Mar 23 '16 at 20:36

answered Mar 23 '16 at 20:31

Funk Forty Niner

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OP's not paying attention here. – Funk Forty Niner Mar 23 '16 at 20:41
Whatever. This answer must be the same color as the background: white. – Funk Forty Niner Mar 23 '16 at 20:44
Calm down buddy, your time to shine will come. – Charlotte Dunois Mar 23 '16 at 20:46
@CharlotteDunois Too many cooks in the kitchen *lol*. TBH, I've given up. – Funk Forty Niner Mar 23 '16 at 20:46
There there buddy, OP is just confused and doesn't know what to do. – Charlotte Dunois Mar 23 '16 at 20:48
@CharlotteDunois Seems to be the case Charlotte. Thanks, cheers. – Funk Forty Niner Mar 23 '16 at 20:52
I think no one noticed FATAL error. Please solve it. mysqli_result() and mysql_result() both are giving the same error.. – Sudin Mar 23 '16 at 21:08
@Sudi ah yes... you're right. You need to replace that `mysqli_result()` with another function. See this answer for an example http://stackoverflow.com/a/17707384/ or simply use `mysqli_error($dbCon)` in its place if the goal is to check if the query failed or not. Also consult http://php.net/manual/en/class.mysqli-result.php – Funk Forty Niner Mar 23 '16 at 21:23
Apparently, forgot to upvote :) Tracking down old answers. – Xorifelse May 29 '17 at 01:35
@Xorifelse Thanks :-) – Funk Forty Niner May 29 '17 at 01:52

score 0 · Answer 2 · answered Mar 23 '16 at 20:28

0

The connection variable is not defined in the function scope. The hotfix is to add it with the "global" construct.

function user_exists($username)
{
global $dbCon;
...

answered Mar 23 '16 at 20:28

Agnis

131
1
2

Thanks, that worked. What about the last error (Fatal error)..? – Sudin Mar 23 '16 at 20:32

score 0 · Answer 3 · answered Mar 23 '16 at 20:32

you are trying to use a local variable $dbCon inside the function user_exists.

you can just change that variable to be global

ex:

under php/core/database connect.php:

<?php
global $dbCon;
$dbCon=mysqli_connect('localhost','root','','project_point');

?>

under php/core/functions Users.php:

<?php
function user_exists($username)
{
    global $dbCon;
    $username = sanitize($username);
    $query = mysqli_query($dbCon,"SELECT COUNT('Login_ID')FROM 'login' WHERE 'Username' = '$username'");
    return(mysqli_result($query,0)==1) ? true : false;
}
 ?>

Xorifelse · Answer 4 · 2016-03-23T20:40:09.637

0

The issue is that $dbCon is not defined in the scope of any function. You could do 3 things:

function user_exists($username){
  $query = mysqli_query($GLOBALS['dbCon'] ... 

function user_exists($username){
  global $dbCon;
  $query = mysqli_query($dbCon ...

However, using globals in functions like this is usually a bad coding style. I would recommend doing something like the following:

function getconn(){
  static $conn;
  if(!isset($conn)){
    $conn = new mysqli_connect(...);
  } 

  return $conn;
}

function user_exists($username){
  $query = mysqli_query(getconn() ...

I was just about to add the issues with your SQL syntax, but Fred beat me to it. I think you want backticks ` instead, not '.

edited Mar 23 '16 at 20:40

answered Mar 23 '16 at 20:33

Xorifelse

7,878
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Great help. what about the Fatal error? Fatal error: Uncaught Error: Call to undefined function mysqli_result() in C:\xampp\htdocs\Project\core\functions\Users.php:8 Stack trace: #0 C:\xampp\htdocs\Project\login.php(4): user_exists(NULL) #1 {main} thrown in C:\xampp\htdocs\Project\core\functions\Users.php on line 8 – Sudin Mar 23 '16 at 20:39
There is no such function in mysqli, however you could [add](http://stackoverflow.com/a/20961496/4982088) the function that works like the old mysql_result(). – Xorifelse Mar 23 '16 at 20:48
Same for that also: Call to undefined function mysql_result() in C:\xampp\htdocs\Project\core\functions\Users.php:9 Stack trace: #0 C:\xampp\htdocs\Project\login.php(4): user_exists('sudin') #1 {main} thrown in C:\xampp\htdocs\Project\core\functions\Users.php on line 9 – Sudin Mar 23 '16 at 20:59

How to pass connection varible in other php document

4 Answers4