DB.php

<?php
class DB{
    private static $_instance = null;
    private $_pdo,
            $query,
            $error = false,
            $result,
            $count = 0;

    private function __construct(){
        try {
            $this->_pdo = new PDO(
            'mysql:host=' . config::get('mysql/host'),//get host name
            'dbname=' . config::get('mysql/db'),//get database name
            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();
            //echo "Connected";
        }
        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->_result = $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)){
                $sql = "{$action} * FROM {$table} WHERE {$field} {$operator} ?";

                if(!$this->query($sql, array($value))->error()){
                    return $this;
                }
            }
        }
        return false;
    }

    public function get($table, $where){
        return $this->action('SELECT *', $table, $where);
    }

    public function delete($table, $where){
        return $this->action('DELETE', $table, $where);
    }
    public function insert($table, $fields = array()){
        if(count($fields)){
            $keys = array_key($fields);

             $sql = "INSERT INTO users (".implode(', ', $keys).") VALUES (".implode(',', array_fill(0, count($keys), '?')).")";

             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 .= ', ';
            }
            $x++;
        }
        die($set);

        $sql = "UPDATE {$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;
    }
}
?>