Undefined Array Key error when uploading image on php



PHP Snippet 1:

$target_dir ='pic/';

PHP Snippet 2:

<!DOCTYPE html>
<html>
<body>

<form action="upload.php" method="post" enctype="multipart/form-data">
  Select image to upload:
  <input type="file" name="fileToUpload" id="fileToUpload">
  <input type="submit" value="Upload Image" name="submit">
</form>

</body>
</html>

PHP Snippet 3:

<?php
$target_d

ir = "uploads/";
    $target_file = $target_dir . basename($_FILES["fileToUpload"]["name"]);
    $uploadOk = 1;
    $imageFileType = strtolower(pathinfo($target_file,PATHINFO_EXTENSION));
    // Check if image file is a actual image or fake image
    if(isset($_POST["submit"])) {
      $check = getimagesize($_FILES["fileToUpload"]["tmp_name"]);
      if($check !== false) {
        echo "File is an image - " . $check["mime"] . ".";
        $uploadOk = 1;
      } else {
        echo "File is not an image.";
        $uploadOk = 0;
      }

  

        if (move_uploaded_file($_FILES["fileToUpload"]["tmp_name"], $target_file)) {

$query = "INSERT INTO table  (`image_path`) VALUES ('$target_file')
";
            echo "The file ". htmlspecialchars( basename( $_FILES["fileToUpload"]["name"])). " has been uploaded.";
          } else {
            echo "Sorry, there was an error uploading your file.";
          }
    
    
        }
        ?>

PHP Snippet 4:

 $data = file_get_contents($_FILES['name_of_control']['tmp_name']);
$data = mysql_real_escape_string($data);

$query = "
  INSERT INTO table
    (`blob_column`)
  VALUES
    ('$data')
";

mysql_query($query);