If ID does not exist? (PHP)

[schart]

To be specific, I have an profile.php page that generates itself after the id gotten from the URL. Ex: profile.php?id=1 goes to the user “Schart” with the info[…]

Now how do I determine if the ID in the url ($id) does exist in the database, and alternatively if it ever has?

http://underbakke.net/profile.php?id=1

[crgeary]

To determine if the ID exists in the database:

Query the database for that ID
Check to see how many records where returned, if no records are returned, then the ID does not exist. However if 1 record is returned, then the ID does exist.

To check if it ever has been in there, i suppose you could go about it 2 ways..

The first way, i guess you could just find out what the largest ID is, and if the ID is any lower than that a post must have existed..

A better way would be to keep a record of all posts, even if you delete one, keep a record of it in the database somewhere and set the status of that post to deleted.

[bungle]

In order to provide the latter functionality as crgeary says, when a user deletes their profile, you would really want to mark their user ids record as inactive rather than deleting it. I would add a boolean field of ‘active’ to the user table and then you can do a check like this to see what you are dealing with:

$id  = mysql_real_escape_string($_GET);

$sql = "SELECT * FROM users WHERE id=$id";

$result = mysql_query($sql);



if (mysql_num_rows($result)==0) {

echo ('User never existed');

}

else if (mysql_num_rows($result)==1) {

$userinfo = mysql_fetch_array($result);

if (!$userinfo) {

echo ('User no longer exists.');

}

else {

echo ('User exists and is active.')

}

}

?>

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