[英]Check if username exists in mysql database?
好的,這個代碼,它的注冊表格,但我無法檢查是否已經使用了用戶名? 所有這一切都是在數據庫中再次創建相同的用戶名,而不是返回“用戶名已被采取”,如果有人可以提供幫助將非常感激。
$checkusernametaken = mysql_query("SELECT FROM users (username) WHERE username=username");
if(mysql_num_rows($checkusernametaken)>=1)
{
echo"Username already exists";
}
else
{
$sql = "INSERT INTO users(username, password) VALUES(:username, :password)";
$stmt = $con->prepare( $sql );
$stmt->bindValue( "username", $this->username, PDO::PARAM_STR );
$stmt->bindValue( "password", hash("sha256", $this->password . $this->salt), PDO::PARAM_STR );
$stmt->execute();
return "Registration Successful Welcome " + $checkusernametaken + "<br/> <a href='index.php'>Login Now</a>";
}
這是我使用的代碼,我在評論中的每個人的幫助下工作,謝謝大家!
try {
$con = new PDO( DB_DSN, DB_USERNAME, DB_PASSWORD );
$con->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION );
$sql = "INSERT INTO users(username, password) VALUES(:username, :password)";
$stmt = $con->prepare( $sql );
$stmt->bindValue( "username", $this->username, PDO::PARAM_STR );
$stmt->bindValue( "password", hash("sha256", $this->password . $this->salt), PDO::PARAM_STR );
$stmt->execute();
return "Registration Successful <br/> <a href='index.php'>Login Now</a>";
}
catch( PDOException $e )
{
return "Username Taken <br/> <a href='register.php'>Try Again?</a>";
}
以下是表格的示例:
CREATE TABLE `users` (
`id` INT AUTO_INCREMENT PRIMARY KEY NOT NULL,
`username` VARCHAR(30) NOT NULL UNIQUE,
`password` VARCHAR(64) NOT NULL
);
最簡單的方法是,如果您更改表以使字段用戶名唯一,這樣如果您嘗試插入相同的用戶名,它將導致重復輸入錯誤,您可以輕松地捕獲這樣:
try
{
$sql = "INSERT INTO users(username, password) VALUES(:username, :password)";
$stmt = $con->prepare($sql);
$stmt->bindValue("username", $this->username, PDO::PARAM_STR);
$stmt->bindValue("password", hash("sha256", $this->password . $this->salt), PDO::PARAM_STR);
$stmt->execute();
return "Registration Successful Welcome {$checkusernametaken}<br/><a href=\"index.php\">Login Now</a>";
}
catch (PDOException $e)
{
if ($e->getCode() == 1062)
{
return "The selected username is not available...";
}
else
{
// More info at: http://php.net/manual/en/class.pdoexception.php
return "Handle any other errors here.";
}
}
$checkusernametaken = mysql_query("SELECT FROM users (username) WHERE username=username");
在這里你應該改為
$checkusernametaken = mysql_query("SELECT * FROM `users` WHERE lcase(`username`) = lcase('".mysql_escape_string($this->username)."')") or die(mysql_error());
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