klasa do obsługi bazy danych (mysqli)

class DB
{
    public static $db;

    public static function connect( )
    {
        self::$db = new mysqli( DB_HOST, DB_USER, DB_PASS, DB_NAME, DB_PORT );

        if ( self::$db->connect_errno )
        {
            exit( 'Blad polaczenia z baza danych: ' . self::$db->connect_error );
        }

        self::$db->set_charset( DB_CHAR );
    }

    public static function query( $q, $debugger=false )
    {
        if ( $debugger )
        {
            if ( $result = self::$db->query( $q ) )
            {
                return $result;
            }
            else
            {
                exit( '<h2>DB DEBUGGER:</h2>' . self::$db->error );
            }
        }
        else
        {
            return self::$db->query( $q );
        }
    }

    public static function num_rows( $q, $debugger=false )
    {
        $q = self::$db->query( $q, $debugger );
        return $q->num_rows;
    }

    public static function last_insert_id( )
    {
        return self::$db->insert_id;
    }

    public static function qfetch( $result, $type='assoc' )
    {
        switch ( $type )
        {
            default:
            case 'assoc':
                return $result->fetch_assoc( );
                break;

            case 'row':
                return $result->fetch_row( );
                break;

            case 'object':
                return $result->fetch_object( );
                break;
        }
    }

    public static function fetch( $q, $debugger=false, $type='assoc' )
    {
        $result = self::query( $q, $debugger );

        switch ( $type )
        {
            default:
            case 'assoc':
                return $result->fetch_assoc( );
                break;

            case 'row':
                return $result->fetch_row( );
                break;

            case 'object':
                return $result->fetch_object( );
                break;
        }
    }

    public static function multi_qfetch( $result, $type='assoc' )
    {
        switch ( $type )
        {
            default:
            case 'assoc':
                $data = array( );
                while( $row = $result->fetch_assoc( ) )
                {
                    $data[] = $row;
                }
                return $data;
                break;

            case 'row':
                $data = array( );
                while( $row = $result->fetch_row( ) )
                {
                    $data[] = $row;
                }
                return $data;
                break;

            case 'object':
                $data = array( );
                while( $row = $result->fetch_object( ) )
                {
                    $data[] = $row;
                }
                return $data;
                break;
        }
    }

    public static function multi_fetch( $q, $debugger=false, $type='assoc' )
    {
        $result = self::query( $q, $debugger );

        switch ( $type )
        {
            default:
            case 'assoc':
                $data = array( );
                while( $row = $result->fetch_assoc( ) )
                {
                    $data[] = $row;
                }
                return $data;
                break;

            case 'row':
                $data = array( );
                while( $row = $result->fetch_row( ) )
                {
                    $data[] = $row;
                }
                return $data;
                break;

            case 'object':
                $data = array( );
                while( $row = $result->fetch_object( ) )
                {
                    $data[] = $row;
                }
                return $data;
                break;
        }
    }

    public static function queryClose( $query )
    {
        $query->close( );
    }

    public static function connectionClose( )
    {
        self::$db->close( );
    }
}