[RESOLVED] Row Already Exists

lupus2k5

Okay, I just started experimenting with MySQL today. Congratulate me.
Okay, so I got far enough to write to a table in a database and then read the table contents of a database. Then I got stuck.
Basically, my script will create a username/password combo for a registration membership on my site (this doesn't have to do with MySQL users; it has to do with membership users, like registering at this site to post).
The user registers by inputting their username and password, and that information is saved to the database. However, I have a problem:
What if that username has already been chosen?

I don't know how to do this, and, as I said, I started MySQL today, so please be really descriptive.

Thanks.

bogu

lupus2k5 wrote:
What if that username has already been chosen?

What do u mean by this?
U want to say, if the username already exists?

Houdini

Run a query on the database and you shuld have a variable lets say $username which is from a post like $_POST['username'] then you would just check the database to see if that username exists.

<?php
$username=$_POST['username'];
$password=$_POST'password'];
$connect=mysql_connect('localhost','user','pass')
  or die("Could not connect to database".mysql_error());
$select=mysql_select_db('mydata',$connect)
  or die("Could not select database.".mysql_error());
$query = "SELECT username,password FROM members WHERE username='$username'";
$result = mysql_query($query)
  or die("Could not perform query.".mysql_query());
$row=mysql_fetch_assoc($result);
if($row['username']==$username||$row['password']==$password){
//you have a match of one of these either username or password
}
else{
//do some thing with the usename or password since no match was found
}
?>

Rodney_H_

I like what houdini has showed you, and would elaborate with two ideas/suggestions:

<?php
// trim extra whitespace and strip slashes (if needed)
if(get_magic_quotes_gpc() == 1)
{
     $username = trim(stripslashes($_POST['username']));
}
else 
{
     $username = trim($_POST['username']);
}


// then use mysql_real_escape string AND limit query to one (1)
$query = "SELECT username FROM members WHERE username = '".mysql_real_escape_string($username)."' LIMIT 1";

?>

lupus2k5

OK, I think I got it. I haven't used the WHERE statement, that's why.... Thanks!