多个prepare语句的优雅解决方案


elegant solution for multiple prepare statements

我试图以更好的方式解决的问题是删除带有标签的图像文件夹。所以对于每张图片我都需要删除

-图像本身

-来自三个数据库(img_offer, img_member, img_horses)的图像标签

目前,我得到要删除的文件夹的所有图像id,然后用四种不同的查询遍历这四次,这似乎相当低效。

主要问题是,据我所知,你不能同时打开多个prepare语句,并且在每次迭代中创建新的语句似乎也违反直觉。

我认为最好的方法是像多个查询准备语句这样的东西,但我找不到类似的东西,所以也许这里有人有一个想法,如何以更干净的方式解决这个问题

我的想法是这样的

$multiplePreparedStatement= "DELETE this FROM that WHERE id=?;
                             DELETE this2 FROM that2 WHERE id2=?;
                             DELETE this3 FROM that3 WHERE id3=?;";
$preparedStmt = $conn->prepare($multiplePreparedStatement);
foreach($imgArray as $imgId){
    $preparedStmt->bind_param("iii", $imgId, $imgId, $imgId);
    $preparedStmt->execute();
}
$preparedStmt->close();

但我不认为这将工作作为多个SQL查询不支持在准备好的语句或他们?

下面是我当前的代码:

       $id=$_GET['deleteAlbum'];
       $getImages = "SELECT image_id AS id
                        FROM Images
                        WHERE folder_id = ?";
       $deleteImage="DELETE FROM Images
                        WHERE image_id=?";
       $deleteOffer = "DELETE FROM Images_Offers
                        WHERE image_id=?";
       $deleteHorse = "DELETE FROM Images_Horses
                        WHERE image_id=?";
       $deleteTeam  = "DELETE FROM Images_Team
                        WHERE image_id=?";
       //get all image ids
        $ImgStmt=$conn->prepare($getImages);
        $ImgStmt->bind_param("i", $id);
        $ImgStmt->execute();
        $ImgStmt->bind_result($id);
        $imgToDelete = array();
        while($ImgStmt->fetch()){
            array_push($imgToDelete, $id);
        }
        $ImgStmt->close();
        $stmt=$conn->prepare($deleteOffer);
        foreach ($imgToDelete as $imgId){
            $stmt->bind_param("i",$imgId);
            $stmt->execute();
        }
        $stmt->close();
        $stmt=$conn->prepare($deleteHorse);
        foreach ($imgToDelete as $imgId){
            $stmt->bind_param("i",$imgId);
            $stmt->execute();
        }
        $stmt->close();
        $stmt=$conn->prepare($deleteTeam);
        foreach ($imgToDelete as $imgId){
            $stmt->bind_param("i",$imgId);
            $stmt->execute();
        }
        $stmt->close();
        $stmt=$conn->prepare($deleteImage);
        foreach($imgToDelete as $imgId){
            unlink("../assets/img/images/img".$imgId.".jpg");
            $stmt->bind_param("i",$imgId);
            $stmt->execute();
        }
        $stmt->close();

我也有创建多个连接的想法,但我认为这可能会出现问题,如果例如删除图像,而我仍然有一个查询迭代图像

根本不需要遍历image_id(至少不需要遍历SQL数据)。您可以一次从数据库中删除与特定folder_id相关的所有内容:

DELETE Images, Images_Offers, Images_Horses, Images_Team
FROM Images
LEFT JOIN Images_Offers ON Images_Offers.image_id = Images.image_id
LEFT JOIN Images_Horses ON Images_Horses.image_id = Images.image_id
LEFT JOIN Images_Team   ON   Images_Team.image_id = Images.image_id
WHERE folder_id = ?;

当然,在此之前你应该unlink实际的文件