class DB
{
    // объявление свойств
    protected $host = 'localhost';
    protected $db =   'db';
    protected $charset = 'utf8';
    protected $user = 'user';
    protected $pass = 'pwd';

    public function __construct() {
        // создание подключения к БД
    }

    // другие методы класса
}

$config = **parse_ini_file**('config.ini', true);

// define DB configuration
$configDb = $config['db'];
define('DB_HOST', $configDb['host']);
define('DB_USER', $configDb['user']);
define('DB_PASSWORD', $configDb['password']);
define('DB_NAME', $configDb['dbname']);
define('DB_PORT', $configDb['port']);

$link = new mysqli(DB_HOST, DB_USER, DB_PASSWORD);

require_once 'config.php';
 require_once 'DB.php';

namespace EngineCoreDatabase;

use PDO;
use EngineCoreConfigConfig;
class Connection
    {
        private $link;

        /**
         * Connection constructor.
         */
        public function __construct()
        {
            $this->connect();
        }

        /**
         * @return $this
         */
        private function connect()
        {
            $config = Config::file('database');

            $dsn = 'mysql:host=' . $config['host'] . ';dbname=' . $config['db_name'] . ';charset=' . $config['charset'];

            $this->link = new PDO($dsn, $config['username'], $config['password']);

            return $this;

        }
        /**
         * @param $sql
         * @param array $values
         * @return mixed
         */
        public function execute($sql, $values = [])
        {
            $sth = $this->link->prepare($sql);
            return $sth->execute($values);
        }
        /**
         * @param $sql
         * @param array $values
         * @return array
         */
        public function query($sql, $values = [])
        {

            $sth = $this->link->prepare($sql);

            $sth->execute($values);
            $result = $sth->fetchAll(PDO::FETCH_ASSOC);
            if ($result === false) {
                return [];
            }

            return $result;
        }
    }

namespace EngineCoreDatabase;
class QueryBuilder
{
    /**
     * @var array
     */
    protected $sql = [];
    /**
     * @var array
     */
    public $values = [];

    /**
     * @param string $fields
     * @return $this
     */
    public function select($fields = '*')
    {
        $this->reset();
        $this->sql['select'] = "SELECT {$fields} ";

        return $this;
    }

    /**
     * @param $table
     * @return $this
     */
    public function from($table)
    {
        $this->sql['from'] = "FROM {$table} ";

        return $this;
    }

    /**
     * @param $column
     * @param $value
     * @param string $operator
     * @return $this
     */
    public function where($column, $value, $operator = '=')
    {
        $this->sql['where'][] = "{$column} {$operator} ?";
        $this->values[] = $value;

        return $this;
    }

    /**
     * @param $field
     * @param $order
     * @return $this
     */
    public function orderBy($field, $order)
    {
        $this->sql['order_by'] = " ORDER BY {$field} {$order}";

        return $this;
    }

    /**
     * @param $number
     * @return $this
     */
    public function limit($number)
    {
        $this->sql['limit'] = " LIMIT {$number}";

        return $this;
    }

    public function update($table)
    {
        $this->reset();
        $this->sql['update'] = " UPDATE {$table} ";

        return $this;
    }

    public function insert($table)
    {
        $this->reset();
        $this->sql['insert'] = "INSERT INTO {$table} ";

        return $this;
    }

    public function set($data = [])
    {
        $this->sql['set'] .= " SET ";

        if (!empty($data)) {
            foreach ($data as $key => $value) {
                $this->sql['set'] .= "{$key} = ?";
                if (next($data)) {
                    $this->sql['set'] .= ", ";
                }
                $this->values[] = $value;
            }
        }
        return $this;
    }

    /**
     * @return string
     */
    public function sql()
    {
        $sql = '';
        if (!empty($this->sql)) {
            foreach ($this->sql as $key => $value) {
                if ($key == 'where') {
                    $sql .= " WHERE ";
                    foreach ($value as $where) {
                        $sql .= $where;
                        if (count($value) > 1 and next($value)) {
                            $sql .= ' AND ';
                        }
                    }
                } else {
                    $sql .= $value;
                }
            }
        }
        return $sql;
    }

    public function reset()
    {
        $this->sql = [];
        $this->values = [];
    }

}

$this->db->execute(
                $this->queryBuilder->update($this->getTable())
                    ->set($properties)
                    ->where('id', $this->id)
                    ->sql(),
                $this->queryBuilder->values
                );

namespace Engine;
use EngineDIDI;

abstract class Controller
{
    /**
     * @var DI
     */
    protected $di;
    protected $db;


    /**
     * Controller constructor.
     * @param DI $di
     */
    public function __construct(DI $di)
    {
        $this->di       = $di;
        $this->db       = $this->di->get('db');

    }
}

namespace EngineCoreConfig;
class Config
{
    /**
     * @param $key
     * @param string $group
     * @return null
     */
    public static function item($key, $group = 'main')
    {
        $groupItems = static::file($group);
        return isset($groupItems[$key]) ? $groupItems[$key] : null;
    }

    /**
     * @param $group
     * @return bool|mixed
     * @throws Exception
     */
    public static function file($group)
    {
        $path = $_SERVER['DOCUMENT_ROOT'] . '/' .  mb_strtolower(ENV) . '/Config/' . $group . '.php';

        if(file_exists($path))
        {
            $items = require_once $path;

            if(!empty($items))
            {
                return $items;
            }
            else
            {
                throw new Exception(
                    sprintf(
                        'Config file <b>%s</b> is not a valid array.', $path
                    )
                );
            }
        }
        else
        {
            throw new Exception(
                sprintf('Cannot load config from file, file <b>%s</b> does not exist.', $path)
            );
        }

        return false;
    }
}