PDO查询不工作，但生成的SQL运行在PHPMyAdmin

我试图运行以下PDO查询，但它根本不更新记录。如果我通过PHPMyAdmin运行代码，它会运行良好并更新记录。

$dbhost = 'localhost';
$dbuser = 'general';
$dbpass = 'removed';
$dbname = 'removed';
try {
$dbo = new PDO('mysql:host=localhost;dbname='.$dbname, $dbuser, $dbpass);
}catch (PDOException $e) {
print "Error!: " . $e->getMessage() . "<br/>";
die();
}
$query="UPDATE `soldier_info` SET `soldier_image`= '$soldier_image' WHERE `soldier_id`=" . $_POST['soldier_id'];
echo $query;
$q=$dbo->prepare($query);
$q->execute();

谁能告诉我我做错了什么?我没有看到任何错误信息回显或打印在页面上，当我回显$query时，它显示:

UPDATE `soldier_info` SET `soldier_image`= 'http://www.bringingthemhome.co.uk/preview/images/soldiers/soldier1.jpg' WHERE `soldier_id`=4

如前所述，通过PHPMyAdmin

<?php
$dbhost = 'localhost';
$dbuser = 'general';
$dbpass = 'removed';
$dbname = 'removed';
try {
    $dbo = new PDO('mysql:host=localhost;dbname='.$dbname, $dbuser, $dbpass);
    $q = $dbo->prepare("UPDATE `soldier_info` SET `soldier_image`= :image WHERE `soldier_id`= :id");
    $q->execute(array(":image" => $soldier_image, :id" => $_POST['soldier_id']));
}catch (PDOException $e) {
    print "Error!: " . $e->getMessage() . "<br/>";
    die();
}
?>