php - A link to the server could not be established -

a simple insert function, , yet. gives nasty errors...

like:

warning: mysql_query(): access denied user '***.'@'***.one.com' (using password: no) in /customers/***.be/***.be/httpd.www/belastingen/classes/btw.php on line 24 warning: mysql_query(): link server not established in /customers/***.be/***.be/httpd.www/belastingen/classes/btw.php on line 24 

and code:

<?php      if(isset($_post['submit'])){      $naam = $_post['name'];     $email = $_post['email'];     $kind1 = $_post['kind1'];     $kind2 = $_post['kind2'];     $kind3 = $_post['kind3'];     $kind4 = $_post['kind4'];     $kind5 = $_post['kind5'];     $captcha = $_post['captcha'];          if ($captcha == 2){             if (!empty($_post['name']) && !empty($_post['email']) && !empty($_post['kind1'])) {                     $insert = "insert belastingen (ouder, email, kind1, kind2, kind3, kind4, kind5) values (                             '".$naam."',                             '".$email."',                             '".$kind1."',                             '".$kind2."',                             '".$kind3."',                             '".$kind4."',                             '".$kind5."')";                 if (!mysql_query($insert)) {                     echo "<div class=\"feedback\">query invoeren faalt</div>";                 } else {                      echo "<div class=\"feedback\">uw registratie werd goed geregistreerd</div>";                 }                   }    else {                 echo "<div class=\"feedback\">falen, niveau 2</div>";             }         } else {             echo "<div class=\"feedback\">captcha probleem</div>";         }     }    ?> 

and don't worry mysql-injection. adding speak. thought error? , yes i'm sure data connection database correct.

update 1 inc.php-file, included on top of index.php file.

<?php   define('mysql_host',  '***.be.mysql');   define('mysql_db',    '***');   define('mysql_user',  '***');   define('mysql_passw', '***');    require_once 'classes/dbconnections.php';   require_once 'classes/btw.php';   $_db = new dbconnection(mysql_host, mysql_db, mysql_user, mysql_passw); ?> 

update 2 dbconnections.php-file

<?php  class dbconnection {    public  $host;   public  $db;   public  $user;   public  $password;    private $_connection;    public function __construct($host = null, $db = null, $user = null, $password = null) {     $this->host     = $host;     $this->db       = $db;     $this->user     = $user;     $this->password = $password;     $this->connect();   }    private function connect(){     $this->_connection = mysql_connect($this->host, $this->user, $this->password);     if(!$this->_connection) {       die("an error occured---- while connecting database: ".mysql_errno()." - ".mysql_error());     } else{       $selected = mysql_select_db($this->db, $this->_connection);       if(!$selected) {         die("an error occured while connecting database: ".mysql_errno()." - ".mysql_error());       }     }    }    public function listing($sql) {     $result = mysql_query($sql, $this->_connection);     while($row=mysql_fetch_array($result)) {       $return[] = $row;     }     return $return;   }    public function select($sql) {     $result = mysql_query($sql, $this->_connection);     return mysql_fetch_array($result);   }    public function insert($sql) {     mysql_query($sql, $this->_connection);     return mysql_affected_rows($this->_connection);   }    public function delete($sql) {     mysql_query($sql, $this->_connection);     return mysql_affected_rows($this->_connection);   }    public function escape($value) {     return mysql_real_escape_string($value);   }  }  ?> 

update 3
error when replacing thins suggested below

notice: undefined variable: _db in /customers/***/***/httpd.www/belastingen/classes/btw.php on line 13 fatal error: call member function insert() on non-object in /customers/***/***/httpd.www/belastingen/classes/btw.php on line 13 

as per our discussion in comments on question, try changing things inc.php required in btw.php; btw.php required in index.php rather inc.php; , 'btw.php` not required in inc.php. reading php.net/manual/en/function.include.php, think might have scope.

edit:

first off, setup have creates custom database object class (dbconnection) used interface database , execute queries. when used mysql_query itself, did not have database connection identifier execute query, since dbconnection object abstracts functionality in object methods. why needed use if (!$_db->insert($insert)).

secondly, , i'm not 100% on this, core problem seems have code in btw.php not "seeing" database setup code. have been because of 2 things. first, $_db variable defined after btw.php code required, , result, when php interpreter parsed btw.php, $_db had not yet been defined. order if requires , database object definition matter. secondly, , bit unsure, think there variable scope/access issue when requiring btw.php within inc.php (where $_db defined) rather requiring database setup within btw.php. in other words, had code uses database object required in script defines it, rather database setup script (including database object declaration) required within code uses it.

i hope makes sense, please let me know if still confusing. tend have problem explaining things concisely.