Nerde yanlış yapıyorum acaba

   <div class="form-group">
                                        <form action="ayar/islem.php" method="POST" enctype="multipart/form-data" >
              <div class="form-group">
                <label class="control-label col-md-3 col-sm-3 col-xs-12" for="urun_slider">Ürün Slider
                </label>
                <div class="col-md-6 col-sm-6 col-xs-12">
                  <?php 
                  if (strlen($uruncek['urun_slider'])>0) {?>
                    <img width="200"  src="../img/urundetay<?php echo $uruncek['urun_slider']; ?>">
                  <?php } else {?>
                    <img width="200"  src="../img/no-image.jpg">
                  <?php } ?>
                </div>
              </div>
              <div class="input-group">
                                            <div class="custom-file">
                                                <input type="file"  id="urun_slider"  name="urun_slider" class="custom-file-input">
                                                <label class="custom-file-label" for="urun_slider">Resim Seç</label>
                                                
                                            </div>
                                            
                                        </div>

              <input type="hidden" name="eski_yol" value="<?php echo $uruncek['urun_slider']; ?>">
              <input type="hidden" name="urun_id" value="<?php echo $uruncek['urun_id']; ?>">
              <div align="right" class="col-md-6 col-sm-6 col-xs-12 col-md-offset-3">
                <button class="btn btn-primary btn-rounded mb-2" name="urunsliderduzenle">Güncelle</button>
              </div>

            </form>
            
            <?php 
            $urun_id = $_POST['urun_id'];
	$resimresimsilunlink=$_POST['eski_yol'];
	$uploads_dir = '../../img/urundetay';
	@$tmp_name = $_FILES['urun_slider']["tmp_name"];
	$benzersizsayi1=rand(10000,59000);
	$refimgyol=substr($uploads_dir)."/".$benzersizsayi1;
	@move_uploaded_file($tmp_name, "$uploads_dir/$benzersizsayi1");
	if ($_FILES['urun_slider']["tmp_name"]=="") {
		$duzenle=$db->prepare("UPDATE urunler SET urun_slider=:urun_slider WHERE urun_id=:urun_id");
		$update=$duzenle->execute(array(
			'urun_slider' => $resimresimsilunlink,
			'urun_id' => $urun_id
		));

		if ($update) {
			header("Location:../urun-duzenle.php?durum=logook&urun_id=$urun_id");
		} else {
			header("Location:../urun-duzenle.php?durum=logono&urun_id=$urun_id");
		}
	} else {
		$duzenle=$db->prepare("UPDATE urunler SET urun_slider=:urun_slider WHERE urun_id=:urun_id");
		$update=$duzenle->execute(array(
			'urun_slider' => $refimgyol,
			'urun_id' => $urun_id
		));

		if ($update) {
			unlink("../../img/urundetay$resimresimsilunlink");
			header("Location:../urun-duzenle.php?durum=logook&urun_id=$urun_id");
		} else {
			header("Location:../urun-duzenle.php?durum=logono&urun_id=$urun_id");
		}
	}
}
?>

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