PHP if语句检测到填充字段为空

Question

我在更新数据库方面遇到了问题。我想在编辑帖子后更新数据库。我回显了输入中的数据，您可以在单击编辑后看到这些数据，因此不需要填充字段但需要修改。它可以在我剪切数据并再次通过它时工作，但是当我修改数据时，例如标题然后它显示填写所有字段的消息。我顺便使用PDO方法。

以下是代码：

<div id="box" class="info-box">
<h1 class="text-title">Insert Post Here!</h1>

<form action="" method="post" enctype="multipart/form-data">

    <p>Your post will not be published if all fields are not filled!</p>

    <p>
        <label>Post Title *</label>
        <input type="text" name="post_title" size="60" value="<?php echo $p_title; ?>">
    </p>

    <p>
        <label>Post Category *</label>
        <select name="cat">

            <?php

                $g_cats = "SELECT * FROM categoryTable WHERE cat_id='$p_cat'";

                $run_g_cats = $conn->query($g_cats);

                while ($cats_row = $run_g_cats->fetch()) {

                    $c_id   = $cats_row['c_id'];
                    $c_title    = $cats_row['c_title'];

                    echo "<option value='$c_id'>$c_title</option>";

                    // Get more Categories..
                    $get_m_cats = "SELECT * FROM categoryTable";

                    $run_m_cats = $conn->query($get_m_cats);

                    while ($more_cats = $run_m_cats->fetch()) {

                        $c_id    = $more_cats['c_id'];
                        $c_title = $more_cats['c_title'];

                        echo "<option value='$c_id'>$c_title</option>";

                    }// while for more categories

                }

            ?>

        </select>
    </p>

    <p>
        <label>Post Author *</label>
        <input type="text" name="post_author" size="60" value="<?php echo $p_author; ?>">
    </p>

    <p>
        <label>Post Keywords *</label>
        <input type="text" name="post_keywords" size="60" value="<?php echo $p_keywords; ?>">
    </p>

    <p id="upfile">
        <label>Post Image *</label>
        <label class="upfile" for="file">Choose a file</label><img src="upimg/<?php echo $p_image; ?>" style="max-width: 135px; height: auto; margin-top: 15px;">
        <input type="file" name="post_image" size="50" id="file" class="inputfile" data-multiple-caption="{count} files selected" multiple>
    </p>

    <p>
        <label>Post Content *</label>
        <textarea name="post_content" rows="20" cols="45"><?php echo $p_content; ?></textarea>
    </p>

    <p class="form-submit">
        <input type="submit" name="update" value="Update The Post!">
    </p>

</form>

if ( isset($_POST['update']) ) {

    $update_id  = $p_id;
    $p_title    = $_POST['p_title'];
    $p_date     = date('d-m-y');
    $p_cat_up   = $_POST['cat'];
    $p_author   = $_POST['p_author'];
    $p_keywords = $_POST['p_keywords'];
    $p_image        = $_FILES['p_image']['name'];
    $p_image_tmp = $_FILES['p_image']['tmp_name'];
    $p_content  = $_POST['p_content'];

    if ( $p_title   == '' OR 
         $p_cat     == '' OR
         $p_author  == '' OR
         $p_keywords == '' OR
         $p_image   == '' OR
         $p_content == ''   ) {

         echo "Please fill in all the fields!";

         exit();

    } else {

        move_uploaded_file($p_image_tmp, "upimg/$p_image");

        $update_posts = "UPDATE table SET cat_id = :p_cat, p_title = :p_title, p_date = :p_date [...] WHERE p_id = :p_id";

        $update_q = $conn->prepare($update_posts);
        $update_q->execute( array(':p_cat'=>$p_cat_up,
                                ':p_title'  =>$p_title,
                                ':p_date'   =>$p_date,
                                ':p_author' =>$p_author,
                                ':p_keywords'=>$p_keywords,
                                ':p_image'  =>$p_image,
                                ':p_content' =>$p_content,
                                ':p_id'     =>$update_id
                                ) );

        echo "Post has been Published!";

    } // Validation

} // Main if-statement

$conn = null;

＆GT？;