Duplication check in form insert - PHP/MySQL

Anon

Just to let you all know, I\'m a beginner at PHP and MySQL...

anyways, I figured out how to insert member signup info(username, password, email, address, etc..) into my table MEMBER_LIST via form inputs. However, I want to make sure that there is no duplicate members, that someone doesn\'t signup twice. I\'m limiting the duplication check to username, email, and first name + last name(together). My question is how do I program this? just the duplication check?

let me know if there is anything I can clear up, thanks in advance,
Sadia Hasan

Anon

The best way is to make them enter something like an email address then have that field unique this way they can't re register

Hope this helps

Anon

I see what you are saying, but I'm also looking for another part to this. I should clear it up a bit more.

I want to accomplish two things with this script 1.) To make sure no one signs up twice, thats why I'm making sure the email addresses are unique

2.) Make sure that member B doesn't choose the same username and/or first name + last name (I need these last two to be unique also) that member A has already chosen. And if so ask him/her to go back and choose another username or first/last name.

I have tried programming this before my Insert query, to check for duplication and if found terminate the script, but I dont seem to be doing it right.

Could someone tell me how I should go about doing this?
thanks again,
Sadia Hasan

Anon

proceed with the signup as before. but only before making an entry to the table, check if the data being entered is already in the table, by running SELECT command on every field. and if the username or email is matched the query will return the result, and so the number of rows will obviously be more than 0. so, you can have an IF statement to check if the number of rows returned is more than 0 then give error message to user (as that record already exists) ... let me give you some example:

$username
$email
$firstname
// above are the fields from your form.

$sql_username = "SELECT * FROM members_table WHERE username='$username'";

then execute this SQL, and do the same for all of them seperately.. if any returns the result to be true, it means the record already is there, so raise the error message and tell user to go back.

hope this get you started,
regards,
Daarius
salaam

Anon

All right, this is the code I wrote up. Again, I should remind you that I\'m a beginner, so I\'m sure there are alot of mistakes here.

Okay one thing I wanted to do was to check for all three duplications at one time. I dont want to exit the script after finding a duplicate username and then make the user come back only to find another duplicate(this time in the email or the name field). I want to be able to check for all three at the same time. Is that possible?

Okay, so this is the code I tried, but it doesn\'t seem to work. Any suggestions?
<?php
$server= //mysql server address
$dbname= // mysql database name
$uid= // username for that database
$pwd= // password for that database

$verifya = \"SELECT * FROM MEMBERS\";
$verifya .= \"WHERE USERNAME = $USERNAME\";

$conn=mysql_connect($server,$uid,$pwd) or die(\"Unable to connect to SQL server\");
mysql_select_db($dbname, $conn) or die(\"Unable to select database\");
$verification = mysql_query($verifya);

if (isset($verification)) {

echo \"Sorry, the username $USERNAME has already been chosen\";
echo \"\";

}

$verifyb = \"SELECT * FROM MEMBERS\";
$verifyb .= \"WHERE FIRST_NAME = $FIRST_NAME AND\";
$verifyb .= \"LAST_NAME = $LAST_NAME\";

$verificationb = mysql_query($verifyb);

if (isset($verificationb)) {

echo \"Sorry, the name $FIRST_NAME $LAST_NAME already exists in the member base\";
echo \"\";
}

$verifyc = \"SELECT * FROM MEMBERS\";
$verifyc .= \"WHERE EMAIL = $EMAIL\";

$verificationc = mysql_query($verifyc);

if (isset($verificationc)) {

echo \"Sorry, the email $EMAIL has previously been submitted\";
echo \"\";
exit;
}
else
{

This is where I insert the member info if there are no duplications.

-SH

Anon

This is the way I would do it, although I would check for empty fields, string lengths and illegal characters.

$db = mysql_connect("localhost", "gopile", "password");
mysql_select_db("database",$db);
$result = mysql_query("SELECT * FROM members WHERE email LIKE '$email'",$db);
if ($myrow = mysql_fetch_array($result)) {
printf("looks good");
} else {
printf("looks bad");
}

Saying that, I'm sure that you don't have to use the printf function.

Anon

LS,

(as i was searching for form stuff i couldn't help noticing this thread, maybe the anwser is still helpfull)

to check on three fields at once try the OR statement.
pseudocode:

SELECT * FROM table WHERE (name=name)OR(mail=mail)OR(fullname=fullname)

if on of them matches, you get a row back and thus have a duplicate entry. at login you ofcourse use the AND match:

SELECT * FROM table WHERE (name=name)AND(password=password)

good luck,
tr909