我的数据库包装器不允许我使用 fetchAll 或任何其他 PDO 函数

Question

我正在尝试遍历结果集并使用PDO打印出行的值，以及我使用教程制作的PHP数据库包装器。当我使用 PDO 函数时，例如 fetchAll((;或 fetch((;我得到致命错误。

我

只是好奇如何使用我提供的代码来做到这一点。我可以使用下面的代码轻松实现插入、数据更新等，但我很难弄清楚如何循环和打印。任何帮助都会很棒，谢谢。

我需要帮助的是代码底部块中的 getServices 函数。

我有一个 DB.php 文件：

    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::$_instance;
    }
    public function query($sql, $params = array()) {
        $this->_error = false;
        if($this->_query = $this->_pdo->prepare($sql)) {
            $x = 1;
            if(count($params)) {
                foreach($params as $param) {
                    $this->_query->bindValue($x, $param);
                    $x++;
                }
            }
            if($this->_query->execute()) {
                $this->_results = $this->_query->fetchAll(PDO::FETCH_OBJ);
                $this->_count = $this->_query->rowCount();
            } else {
                $this->_error = true;
            }
        }
        return $this;
    }
    public function action($action, $table, $where = array()) {
        if(count($where) === 3) {
            $operators = array('=', '>', '<', '>=', '<=');
            $field = $where[0];
            $operator = $where[1];
            $value = $where[2];
            if(in_array($operator, $operators)) {
                $sql = $sql = "{$action} FROM `{$table}` WHERE {$field} {$operator} '{$value}'";;
                if(!$this->query($sql, array($value))->error()) {
                    return $this;
                }
            }
        }
        return false;
    }
    public function get($table, $where) {
        return $this->action('SELECT *', $table, $where);
    }
    //deletes items from the database
    public function delete($table, $where) {
        return $this->action('DELETE', $table, $where);
    }
    public function insert($table, $fields = array()) {
        //check if fields has any data
        if(count($fields)) {
            $keys = array_keys($fields);
            $values = null;
            $x = 1;
            foreach($fields as $field) {
                $values .= "?";
                //check if x is less than the count of fields
                if($x < count($fields)) {
                    $values .= ', ';
                }
                $x++;
            }
            $sql = "INSERT INTO {$table} (`" . implode('`, `', $keys) . "`) VALUES ({$values})";
            if(!$this->query($sql, $fields)->error()) {
                return true;
            }
        }
        return false;
    }
    public function update($table, $id, $fields) {
        $set = '';
        $x = 1;
        foreach($fields as $name => $value) {
            $set .= "{$name} = ?";
            if($x < count($fields)) {
                $set .= ', ';
            }
            $x++;
        }
        $sql = "UPDATE {$table} SET {$set} WHERE `id` = {$id}";
        if(!$this->query($sql, $fields)->error()) {
            return true;
        }
        return false;
    }
    public function results() {
        return $this->_results;
    }
    public function first() {
        return $this->results()[0];
    }
    public function error() {
        return $this->_error;
    }
    public function count() {
        return $this->_count;
    }
}

我有报价.php：

  <?php
  class Offer {
    private $_db,
            $_data;
    public function __construct() {
      $this->_db = DB::getInstance();
    }
    public function createOffer($fields = array()) {
      //If the offer is not entered into the database
      if(!$this->_db->insert('offers', $fields)) {
        throw new Exception('There was a Problem creating the offer.');
      }
    }
    public function getOffers() {
      $offers = $this->_db->get('offers', array('address', '=', 'Los Angeles'));
$result = $offers->fetchAll();
  print_r($result);

  }
  }
?>

Answer 1

似乎

在报价中.php它应该是

$result = $offers->results();

不

$result = $offers->fetchAll();