PHP向MySQL注册表格

Question

I have made a register form with php and mysql. It works only if it is introduced diffrent name of user each time. How can i rezolve that? because sometimes i want to insert the same name in the database.

My code:

require('connect.php');
if (isset($_POST['adresa'])) {
    $username = $_POST['username'];
    $email = $_POST['email'];
    $adresa = $_POST['adresa'];
    $judet = $_POST['judet'];
    $telefon = $_POST['telefon'];
    $localitate = $_POST['localitate'];
    $bon = $_POST['bon'];
    $date = $_POST['date'];
    $premiu = $_POST['premiu'];
    $query = "INSERT INTO user (username, adresa, email,judet,telefon,localitate,bon,date,premiu,acord) VALUES ('$username', '$adresa', '$email','$judet','$telefon','$localitate','$bon','$date','$premiu','$acord')";
    $result = mysql_query($query);
}

Answer 1

Use for check user name existence

<?php
require('connect.php');
if (isset($_POST['adresa'])) {
$username = $_POST['username'];
$email = $_POST['email'];
$adresa = $_POST['adresa'];
$judet = $_POST['judet'];
$telefon = $_POST['telefon'];
$localitate = $_POST['localitate'];
$bon = $_POST['bon'];
$date = $_POST['date'];
$premiu = $_POST['premiu'];

$chk_query = mysql_query("Select (username) from user where username=$username");
$num = mysql_num_rows($chk_query);

if($num < 1)
{
$query = "INSERT INTO user (username, adresa, email,judet,telefon,localitate,bon,date,premiu,acord) VALUES ('$username', '$adresa', '$email','$judet','$telefon','$localitate','$bon','$date','$premiu','$acord')";
$result = mysql_query($query);
} 
else { echo "User name exist"; }
}

?>

Answer 2

If you can't insert multiple users with the same name to the database then the username field must have been flagged as UNIQUE at table declaration.

To remove this restriction use DROP INDEX

Note that, if the username field is a primary key you will need to drop the primary key and introduce another, a BIGINT for example (Best option).

IMPORTANT : mysql_ functions are deprecated and you should stop using them. Use mysqli_ or PDO instead