pdo - Fatal error: Call to a member function prepare() on a non-object in C:\xampp\htdocs\cms\include\article.php on line 8 -

i getting error , wondering how fix it? when trying add articles feed.

class article {     public function fetch_all() {         global $pdo;           $query = $pdo->prepare("select * articles order `article_id` desc");         $query->execute();          return $query->fetchall();     }      public function fetch_data($article_id) {         global $pdo;          $query = $pdo->prepare("select * articles article_id = ?");         $query->bindvalue(1, $article_id);         $query->execute();          return $query->fetch();     } }      ?> 

don't use global attempt. that's not oop design , 1 of reasons whey code fails. instead make sure have been created $pdo far , pass constructor of article.

further note capability of called typehints. while using them can enforce special type method param. if pass value @ runtime (like null or else) php throw error:

    typehint-----------------| public function __construct(pdo $pdo) {     $this->pdo = $pdo; } 

example:

class article {      protected $pdo;      // type hint makes !!sure!! pdo connected     public function __construct(pdo $pdo) {         $this->pdo = $pdo;     }      public function fetch_all() {          $query = $this->pdo->prepare("select * articles order `article_id` desc");         $query->execute();          return $query->fetchall();     }      public function fetch_data($article_id) {         // note this:         $query = $this->pdo->prepare("select * articles article_id = ?");         $query->bindvalue(1, $article_id);         $query->execute();          return $query->fetch();     } } 

call this:

$pdo = new pdo($connectionstring, $user, $pass); $article = new article($pdo);  var_dump($article->fetch_data($someid));