stop duplicate enteries into a database and check to see if user exists

[steeko1990]

hi guys I am i am sorry to be a bother but i am new to php and I am currently in the process of creating, login and register pages that store a users name and password in to a database but I am finding it hard to source any code to check if the name exists and if it does tell the user that it does and that they have to choose a alternative user name. The code I have for updating the database is:

 

 

 

 

<?php

extract ($_POST);

$con = mysql_connect("localhost","root","");

if (!$con)

{

  die('Could not connect: ' . mysql_error());

}

mysql_select_db("firstone", $con);

$username = $_POST['username'];

$password = $_POST['password'];

// just to show the collection and storage of information from the form

mysql_query("INSERT INTO details (username , password) VALUES ('$username', '$password')");

echo "your account has been created click next to continue";

mysql_close($con);

?>

[Phear46]

do a query to 'select' all the rows matching your input before you add it to the table. then:

 

if rows returned > 0 {

user exists

} else {

process form as you already are

}

 

a query like:

SELECT * FROM table WHERE user=$usrname, pass=$pass

is what your looking for, although i highly doubt ive got the correct syntax there as im also a noob, one of the pros should be able to help with that!

[davidannis]

Phear46 has a reasonable suggestion. Don't select on the password, just the username.

 

A few more suggestions:

Use mysqli instead of mysql

when creating your table make the field username a PRIMARY or UNIQUE index.

Salt and hash passwords.

Edited May 5, 2013 by davidannis

[steeko1990]

sorry to be a bother i know i am really out of my depth but could anyone direct me to anywhere that i could find the corrent syntax for if rows >0.

[blacknight]

http://php.net/manual/en/function.mysql-num-rows.php

 

php.net your friend when lurning allways good code examples there

[RonnieCosta50]

<?php
include 'dbConnect.php'; // Database Connection php file.
include 'dbTableName.php'; // Contains 1 line of code.  The name of your table in the database.  I call it $dbTableName.
include 'dbTableColumns.php'; // The names of all your columns in your database.  Like your primary key is $dbColumn1.

$qryDuplicateString = mysql_query("SELECT COUNT(*) AS count FROM $dbTableName WHERE $dbColumn2 = '$wsTextbox1' AND $dbColumn3 = '$wsDropDownList1'");
$duplicateRows = mysql_fetch_assoc($qryDuplicateString);
$numOfRows = $duplicateRows['count'];
if ($numOfRows<1) // If a row doesn't exist,
{echo"Create Account";}
else
{echo"Choose alternative username";}
?>

Hope this helps. 

Edited May 6, 2013 by RonnieCosta50

[steeko1990]

sorry to be a pain but a cant get either of the suggestions to work. could some one be able to put a step by step for me i know i am asking a lot.