如何使 topic_cat= 当前类别，例如http://prntscr.com/h08ae我希望将类别 ID 作为 topic_cat 插入。但是当我提出主题时，它只会导致类别 id = 0，这是我的代码：
<?php
if($_SESSION['signed_in'] == false)
{header('Location: http://forums.pirate-zone.com/index.php?');
//the user is not signed in
echo 'Sorry, you have to be <a href="/forum/signin.php">signed in</a> to create a topic.';
}
else
{
//the user is signed in
if($_SERVER['REQUEST_METHOD'] != 'POST')
{
//the form hasn't been posted yet, display it
//retrieve the categories from the database for use in the dropdown
$sql = "SELECT
cat_id,
cat_name,
cat_description
FROM
categories
WHERE
cat_id = " . mysql_real_escape_string($_GET['id']);
$result = mysql_query($sql);
if(!$result)
{
echo 'Error while selecting from database. Please try again later.';
}
else
{ $topic_cat=$row['cat_id'];
if(mysql_num_rows($result) == 0)
{
//there are no categories, so a topic can't be posted
if($_SESSION['user_level'] == 1)
{
echo 'You have not created categories yet.';
}
else
{
echo 'Before you can post a topic, you must wait for an admin to create some categories.';
}
}
else
{
echo '
<div class="contain contentpadding">
<form action="" method="post">
<div style="margin: 10px 0 10px 120px">
<h3>Topic Name (required)</h3>
<br/>
<div class="light contentpadding inputdiv">
<input type="text" name="topic_subject" size="50" />
</div>
<br/>
<br/>
<h3>Topic Body (required)</h3>
</div>
<br/>
<div class="light contentpadding inputdiv">
<div class="cpadding">
<input type="button" class="bbbutton light" title="[color=][/color]" value="Color" />
<input type="button" class="bbbutton light" title="[size=11px][/size]" value="Size" />
<input type="button" class="bbbutton light" title="[b][/b]" value="Bold" />
<input type="button" class="bbbutton light" title="[i][/i]" value="Italic" />
<input type="button" class="bbbutton light" title="[u][/u]" value="Underline" />
<input type="button" class="bbbutton light" title="[img][/img]" value="Image" />
<input type="button" class="bbbutton light" title="[url=http://][/url]" value="URL" />
<input type="button" class="bbbutton light" title="[center][/center]" value="Center" />
<input type="button" class="bbbutton light" title="[quote=][/quote]" value="Quote" />
<input type="button" class="bbbutton light" title="[spoiler][/spoiler]" value="Spoiler" />
<input type="button" class="bbbutton light" title=" [youtube]http://www.youtube.com/watch?v=[/youtube]" value="YouTube Video" />
</div>
<div class="cpadding">
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/amazed.gif" alt=":amazed" border="0" title=":amazed" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/amused.gif" alt=":amused" border="0" title=":amused" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/blink.gif" alt=":blink" border="0" title=":blink" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/cheesy.gif" alt=":cheesy" border="0" title=":cheesy" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/confused.gif" alt=":confused" border="0" title=":confused" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/cool.gif" alt=":cool" border="0" title=":cool" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/cry.gif" alt=":cry" border="0" title=":cry" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/embarressed.gif" alt=":embarrassed" border="0"
title=":embarrassed" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/evil.gif" alt=":evil" border="0" title=":evil" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/huh.gif" alt=":huh" border="0" title=":huh" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/laugh.gif" alt=":laugh" border="0" title=":laugh" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/mad.gif" alt=":mad" border="0" title=":mad" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/notrust.gif" alt=":notrust" border="0" title=":notrust" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/noworry.gif" alt=":noworry" border="0" title=":noworry" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/nuts.gif" alt=":nuts" border="0" title=":nuts" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/oh.gif" alt=":oh" border="0" title=":oh" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/push.gif" alt=":push" border="0" title=":push" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/rolleyes.gif" alt=":rolleyes" border="0" title=":rolleyes" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/sad.gif" alt=":sad" border="0" title=":sad" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/sick.gif" alt=":sick" border="0" title=":sick" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/smile.gif" alt=":smile" border="0" title=":smile" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/suspicious.gif" alt=":suspicious" border="0" title=":suspicious"
/>
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/teeth.gif" alt=":teeth" border="0" title=":teeth" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/tounge.gif" alt=":tounge" border="0" title=":tounge" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/unsure.gif" alt=":unsure" border="0" title=":unsure" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/wacko.gif" alt=":wacko" border="0" title=":wacko" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/weird.gif" alt=":weird" border="0" title=":weird" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/wondering.gif" alt=":wondering" border="0" title=":wondering" />
<img class="bbemoticon" src="http://www.soul-boards.com/images/smilies/worried.gif" alt=":worried" border="0" title=":worried" />
<br />
</div>
<br/> <center><textarea id="post_content" name="post_content" cols="102" rows="13"></textarea></center>
</div>
<br/>
</div>
<div class="center">
<input type="submit" value="Post Topic" />
</div>
</form>
</div>';
}
}
}
else
{
//start the transaction
$query = "BEGIN WORK;";
$result = mysql_query($query);
if(!$result)
{
echo 'An error occured while creating your topic. Please try again later.';
}
else
{
//the form has been posted, so save it
//insert the topic into the topics table first, then we'll save the post into the posts table
$sql = "INSERT INTO
topics(topic_subject,
topic_date,
topic_cat,
topic_by)
VALUES('" . mysql_real_escape_string($_POST['topic_subject']) . "',
NOW(),
'" . $topic_cat . "',
" . $_SESSION['user_id'] . "
)";
$result = mysql_query($sql);
if(!$result)
{
//something went wrong, display the error
echo 'An error occured while inserting your data. Please try again later.<br /><br />' . mysql_error();
$sql = "ROLLBACK;";
$result = mysql_query($sql);
}
else
{
//the first query worked, now start the second, posts query
//retrieve the id of the freshly created topic for usage in the posts query
$topicid = mysql_insert_id();
$sql = "INSERT INTO
posts(post_content,
post_date,
post_topic,
post_by)
VALUES
('" . mysql_real_escape_string($_POST['post_content']) . "',
NOW(),
" . $topicid . ",
" . $_SESSION['user_id'] . "
)";
$result = mysql_query($sql);
if(!$result)
{
//something went wrong, display the error
echo 'An error occured while inserting your post. Please try again later.<br /><br />' . mysql_error();
$sql = "ROLLBACK;";
$result = mysql_query($sql);
}
else
{
$sql = "COMMIT;";
$result = mysql_query($sql);
//after a lot of work, the query succeeded!
echo 'You have succesfully created <a href="topic.php?id='. $topicid . '">your new topic</a>.';
}
}
}
}
}
?>