Fatal error: Uncaught Error: Appel à un membre de la fonction select() sur la valeur null

Je suis un peu nouveau à la programmation orientée objet en php et je suis confronté à ce problème à chaque fois, dans le modèle, mais je ne peux pas trouver l'erreur à l'origine de ce.

J'obtiens un message d'erreur disant: Fatal error: Uncaught Error: Appel à un membre de la fonction select() sur la valeur null dans ma modèle dans le getCategories (Voir code ci-dessous).

<?php

class model_additem extends model{
    public function __construct(){
        DB::setConnection(DB_ADMIN,DB_ADMIN_PASS);
    }

    public function insertItem($picName,$n,$d,$p,$ui,$ic,$pt,$pd="good"){
        $data = ["pic_name"=>$picName,"pic_desc"=>$pd,"pic_type"=>$pt];
        $img = parent::$db->saveTo("pictures")->setData($data)->execute();

        if($img){
            $imgId = parent::$db->lastInsertId();

            $data = ["name"=>$n,"description"=>$d,"price"=>$p,"image_id"=>$imgId,"owner_id"=>$ui,"category_id"=>$ic];
            $prod = parent::$db->saveTo("products")->setData($data)->execute();
            return $prod;
        }
        return false;
    }

    public function getCategories(){
        $data = parent::$db->select()->from('category')->fetch('all');
        if($data) return $data;
        return false;
    }


}

Et voici mon CONTRÔLEUR fichier:

<?php
class controller_additem extends controller{
public function __construct(){
Load::view("admin".DS."header");
Load::view('additem/additem');
Load::view("admin".DS."footer");
require_once 'CheckAdmin.php'; //Check if the user is admin to enter page + more.
}
public function index(){
$item = $this->model("additem");
if(isset($_POST["addItem"])){
$iName = filter_input(INPUT_POST,"iName",FILTER_SANITIZE_MAGIC_QUOTES);
$iDesc = filter_input(INPUT_POST,"iDesc",FILTER_SANITIZE_MAGIC_QUOTES);
$iPrice = filter_input(INPUT_POST,"iPrice",FILTER_SANITIZE_NUMBER_FLOAT);
$iCat = filter_input(INPUT_POST,"category",FILTER_SANITIZE_NUMBER_INT);
$iPic = $_FILES["iPicture"];
$extention = explode(".",$iPic["name"]);
$ext = end($extention);
//pre($iPic);
//validation
//if($iPic["size"]> 2000000){}
$picName = $iName.time().'.'.$ext;
if(move_uploaded_file($iPic["tmp_name"],ROOT . "public/images/" . $picName)){
$userId = Session::get("userId");
$result = $item->insertItem($picName,$iName,$iDesc,$iPrice,$userId,$iCat,$ext);
if($result){
Session::set("result","Item has been inserted successfully");
}else{
Session::set("result","Error occured");
}
}
}
$cats = $item->getCategories();
$uName = Session::get("userData")["name"];
Load::view("additem/additem",$cats);
}
}

J'ai aussi une classe db dans mon moteur de fichier qui gère les fonctions liées à la base de données et la fonction de sélection est là:

class db{
private static $db = null;
private $sql = "";
private $save_type;
private $binded = array();
private $query = '';
private $last_insert_id;
public function __construct(){
if(self::$db == null){
$user = DB_GUEST;
$pass = DB_GUEST_PASS;
if(Session::found("user_priv") == 'no'){
$user = DB_USER;
$pass = DB_USER_PASS;
}
if(Session::found("user_priv") == 'yes'){
$user = DB_ADMIN;
$pass = DB_ADMIN_PASS;
}
self::setConnection($user,$pass);
}
}
public static function setConnection($user,$pass,$dbname=DB_NAME){
try{
self::$db = new PDO("mysql:host=localhost;dbname=$dbname",$user,$pass);
self::$db->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE,PDO::FETCH_ASSOC);
self::$db->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION);
self::$db->exec("SET NAMES utf8");
}catch(PDOException $e){
die($e->getMessage());
}
}
public static function getDb(){
if(self::$db == null){
$user = DB_GUEST;
$pass = DB_GUEST_PASS;
if(Session::found("userId")){
$user = DB_USER;
$pass = DB_USER_PASS;
}
if(Session::found("admin")){
$user = DB_ADMIN;
$pass = DB_ADMIN_PASS;
}
self::setConnection($user,$pass);
}
return self::$db;
}
//SELECT [name,pass,email]
public function select(array $select=[]){
$sql = "SELECT ";
if(empty($select)){
$sql .= "*";
}else{
filter_array($select);
$select = implode(",",$select);
$sql .= string($select);
}
$this->sql = $sql;
return $this;
}
//FROM
public function from($tbl){
$this->sql .= " FROM " . string($tbl);
return $this;
}
//WHERE
public function where(array $where){
//filter_array($where);
$sql = " WHERE ";
foreach($where as $key => $val){
$sql .= $key . " LIKE '".$val."' AND ";
}
$this->sql .= rtrim($sql," AND ");
return $this;
}
//JOIN
public function join(array $tbl,$type="LEFT JOIN"){
$sql = " ".strtoupper($type)." ";
$sql .= implode(",",$tbl);
$this->sql .= $sql;
return $this;
}
//ON
public function on($cond1,$cond2){
$sql = " ON ";
$sql .= string($cond1) . " = " . string($cond2);
$this->sql .= $sql;
return $this;
}
//ORDER BY
public function order_by($order_by, $order_type="ASC"){
$sql = " ORDER BY ";
$sql .= string($order_by)." ".strtoupper(string($order_type));
$this->sql .= $sql;
return $this;
}
//LIMIT
public function limit($limit){
$this->sql .= " LIMIT " . int($limit);
return $this;
}
//FETCH
public function fetch($fetch_type=""){
$fetch = "fetch";
if($fetch_type){
$fetch = "fetchAll";
}
try{
$query = self::$db->query($this->sql);
$this->reset();
return $query->$fetch();
}catch(PDOException $e){
die($e->getMessage());
}
}
//saveTo
public function saveTo($tbl,$type="insert"){
$tbl = string($tbl);
$this->save_type = strtolower(string($type));
if($this->save_type == "update"){
$sql = "UPDATE ";
}elseif($this->save_type == "replace"){
$sql = "REPLACE INTO ";
}else{
$sql = "INSERT INTO ";
}
$sql .= $tbl . " SET ";
$this->sql = $sql;
return $this;
}
//SET DATA
public function setData(array $data,$filter="string"){
$filter = string($filter);
foreach($data as $colomn => $value){
$colomn = string($colomn);
$value = $filter($value);
$this->binded[$colomn] = $value;
$this->sql .= $colomn . "=:" . $colomn . ",";
}
//pre($this->binded);
$this->sql = rtrim($this->sql,",");
return $this;
}
//execute
public function execute(){
try{
$this->query = self::$db->prepare($this->sql);
if($this->binded){
foreach($this->binded as $colomn => $value){
$this->bind($colomn,$value);
}
}
$result = $this->query->execute();
if($this->save_type == 'insert'){
$this->last_insert_id = self::$db->lastInsertId();
}
$this->reset();
return $result;
}catch(PDOException $e){
die($e->getMessage());
}
}
//BIND
private function bind($placeholder,$value,$filter="string",$bind_type="bindValue"){
return $this->query->$bind_type(":".$placeholder,$filter($value),PDO::PARAM_STR);
}
public function lastInsertId(){
return $this->last_insert_id;
}
//DELETE
public function delete($tbl,$col=false){
$this->sql = "DELETE ";
if($col){
$this->sql .= string($col)." ";
}
$this->sql .= "FROM " . string($tbl);
return $this;
}
//TRUNCATE
public function truncate($tbl){
$this->sql = 'TRUNCATE ' . string($tbl);
return $this;
}
//View Query
public function viewQ(){
echo $this->sql;
}
//RESET
private function reset(){
$this->sql = "";
$this->save_type = "";
$this->query = "";
$this->binded = array();
}
}

La chose est que si vous regardez dans le modèle à la saveTo fonction, il semble fonctionner. Toutefois, sélectionnez n'a pas ni les fonctions qui vient après lui.

S'il vous plaît aidez moi, j'ai essayé de chercher pour cette erreur, mais ne pouvait pas trouver la solution à mon problème particulier.

Toute aide est très appréciée!
Merci à l'avance.

MODIFIER: Merci à tous pour votre aide! J'ai pensé à elle. Il y avait une erreur dans la classe du modèle, de sorte qu'il n'y avait pas de connexion à la db.

OriginalL'auteur Jamal Jubran | 2016-01-15