嘗試將圖像上載到數據庫，然後顯示數據庫。得到一個致命錯誤

Question

錯誤：

Fatal error: Uncaught Error: Call to a member function bind_param() on boolean in C:\xampp\htdocs\FinalProject\upload-profilePic.php:22 Stack trace: #0 {main} thrown in C:...

我的代碼：

上傳圖片

<?php 
if ($_SERVER['REQUEST_METHOD'] == 'POST') { 
if (file_exists($_FILES['upload_file']['tmp_name'])) { 
    // get temp name and file name 
    $tmpName = $_FILES['upload_file']['tmp_name']; 
    $fileName = $_FILES['upload_file']['name']; 
    $type = $_FILES['upload_file']['type']; 

    $handler = fopen($tmpName, 'r'); // opens image file stream 
    $data = fread($handler, filesize($tmpName)); // read byte data 
    fclose($handler); // close image file stream 

    $stmt = $con->prepare('insert into images (image_type, 
     filename, image_data) values(?, ?, ?)'); 
    $stmt->bind_param('sss', $type, $fileName, $data); 
    $stmt->execute(); 
    $result = $stmt->get_result(); 
    if (!$result) { 
     echo $con->error; 
    } 
    } 
} 

$result = $con->query('select * from images'); 
if ($result) { 
    foreach ($result as $img) { 
     $name = $img['filename']; 
     $id = $img['image_id']; 
     $url = "get-profilePic.php?id=$id"; 
     echo "<h3>$name</h3>"; 
     echo "<img src=\"$url\" alt=\"$name\" />\n\n"; 
    } 
} 
?> 

獲取圖像

<?php 

$imageId = $_GET['id']; 
$result = $con->query("select * from images 
where image_id = $imageId"); 

if ($result) { 
    $image = $result->fetch_object(); 
    $type = $image->image_type; 
    $data = $image->image_data; 
    header('Content-Type: ' . $type); 
    echo $data; 
} 
?> 

Answer 1

通過考慮你的情況下，問題的關鍵在於：

$stmt = $con->prepare('insert into images (image_type, filename, image_data) values(?, ?, ?)'); 
$stmt->bind_param('sss', $type, $fileName, $data); 

prepare()方法可以返回false，並且需要檢查它爲什麼返回false，或許表名或列名（在SELECT或WHERE子句中）不正確？主要在你的查詢中出現一些錯誤。

此外，請嘗試使用類似$stmt ->error_list的內容來檢查分析SQL時發生的錯誤。

Answer 2

您的錯誤消息說bind_param正在運行boolean。這通常是通過$stmt造成的是false，因爲$con->prepare()失敗：

$stmt = $con->prepare('insert into images (image_type, 
    filename, image_data) values(?, ?, ?)'); 
$stmt->bind_param('sss', $type, $fileName, $data); 

我可以看到$con是不是在你的代碼中定義。你可以在這兩行代碼之前驗證它是否存在？

var_dump($con);