checking a database for a user name

[horseatingweeds]

How can you check a database for something. I have a database with several fields and a page for creating new rows. I'd like to make it able to search the database for one of the fields, the user name, and add a new row it the name is not present and update the row if the user name is present.

 

Any good ideas?

[Daniel0]

You'd do it like this:

<?php
$result = mysql_query("SELECT * FROM users WHERE username='{$username}' LIMIT 1");
if(mysql_num_rows($result) == 1)
{
echo "Username is taken";
}
else {
echo "Username is available";
}
?>

[horseatingweeds]

Thanks Daniel0.

[ToonMariner]

I don't bother with the LIMIT 1 part - I do have a check on usernames on registration but just in case it was bypassed (just incase - can't see a flaw but you never know!).

 

If more than one result is returned, I email myself with the details the user entered to get to that portion of the script so I can do some checks, some admin and some cleanups.

 

Always plan for your application failing or doing something you don't expect - then you can improve on what you have done before...