Question

How do I check if an ip is in the database?

I’m creating a little voting system and right now people can vote more than once.

So i put thier Ip in the database and if its already in the database dont want it to allow the upvote. I get the ips in the database using:

$check = mysql_query("SELECT `ip` FROM `voted`") or die(mysql_error());

I just don’t know how to check if the ip that person is voting with is already entered.

Answer 1

Take a look at the WHERE clause in MySQL:

http://www.tizag.com/mysqlTutorial/mysqlwhere.php

$ip = mysql_real_escape_string([the IP address]);
$q = mysql_query("SELECT `ip` FROM `voted` WHERE `ip`= '$ip'");
if(mysql_num_rows($q) > 0){
    // They already are in the database
}

Remember– sanitize your inputs. Personally, I would use parameters and bindings, but if you are going plain-vanilla MySQL then just use the escaping function. But remember, the mysql_ functions are being deprecated, so I would avoid them if possible. (See PDO)