[英]PDO can't access the database connection instance
我有一個數據庫包裝程序,還有一個獲取PDO連接實例的靜態方法。 Howewer,我想進行PDO查詢時無法訪問它。
這是數據庫類的一部分:
class DB {
private static $_instance = null;
private $_pdo,
$_query,
$_error = false,
$_results,
$_count =0;
private function __construct() {
try {
$this->_pdo = new PDO('mysql:host='.Config::get('mysql/host').';dbname='.Config::get('mysql/db'),Config::get('mysql/username'),Config::get('mysql/password'));
} catch (PDOException $e) {
die($e->getMessage());
}
}
public static function getInstance() {
if(!isset(self::$_instance)) {
self::$_instance = new DB();
}
return self::$_instance;
}
這是我的查詢:
$pdo = DB::getInstance();
$statement = $pdo->prepare("select surname from staff_info where fname = :name");
$statement->execute(array(':name' => Input::get('name')));
$total = $statement->rowCount();
while ($row = $statement->fetch(PDO::FETCH_ASSOC)) {
echo $row['surname'].'</br>';
}
但是運行查詢時出現此錯誤:
致命錯誤:調用未定義的方法DB :: prepare()
我做錯了什么? 有什么幫助嗎?
但這在我這樣做時有效
$dsn = 'mysql:host=localhost;dbname=cois';
$user = 'root';
$password = '';
$pdo = new PDO($dsn, $user, $password);
$filmName = "omar";
$statement = $pdo->prepare("select surname from staff_info where fname = :name");
$statement->execute(array(':name' => $filmName));
$total = $statement->rowCount();
while ($row = $statement->fetch(PDO::FETCH_ASSOC)) {
echo $row['surname'].'</br>';
}
這怎么可能?
您在對象DB而不是PDO上調用prepare,我建議將getter添加到類DB中:
public function getPDO(){
return $this->_pdo;
}
並修改准備查詢:
$db = DB::getInstance();
$statement = $db->getPDO()->prepare(...);
private function __construct() {
try {
self::$_instance = new PDO('mysql:host='.Config::get('mysql/host').';dbname='.Config::get('mysql/db'),Config::get('mysql/username'),Config::get('mysql/password'));
} catch (PDOException $e) {
die($e->getMessage());
}
}
public static function getInstance() {
if(!isset(self::$_instance)) {
new DB();
}
return self::$_instance;
}
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