註冊時防止重複用戶名條目（PHP/MySQL的

Question

我環顧四周，看到了它做了很多例子，但不幸未能落實到我目前使用的代碼。

我想防止用戶具有相同的用戶名註冊時我的網頁上，但我使用的代碼允許項是相同的。

如何修改下面的代碼，以防止這種情況發生？

<?php 
      require('db.php'); 
      // If form submitted, insert values into the database. 
      if (isset($_POST['username'])){ 
       $username = $_POST['username']; 
       $email = $_POST['email']; 
       $password = $_POST['password']; 
       $username = stripslashes($username); 
       $username = mysql_real_escape_string($username); 
       $email = stripslashes($email); 
       $email = mysql_real_escape_string($email); 
       $password = stripslashes($password); 
       $password = mysql_real_escape_string($password); 
       $trn_date = date("Y-m-d H:i:s"); 

       $res_login = $conn->query("select * from users where username='$username'"); 
       if($res_login -> num_rows > 0) 
       { 
         echo "Username is already exists please try with another username"; 
       } 
       else 
       { 
         $query = "INSERT into `users` (username, password, email, trn_date) VALUES ('$username', '".md5($password)."', '$email', '$trn_date')"; 
         $result = mysql_query($query); 
         if($result) 
         { 
            echo "You are registered successfully.</h3><br/>Click here to <a href='login.php'>Login</a></div>"; 
         } 
         else 
         { 
            echo "error in registration"; 
         } 
       } 
     } 
     ?> 

任何幫助將非常appre ciated。

Answer 1

您還可以設置用戶名作爲唯一鍵指數，這將防止重複的行表進入。

及以下

<?php 
    require('db.php'); 
    // If form submitted, insert values into the database. 
    if (isset($_POST['username'])){ 
     $username = $_POST['username']; 
     $email = $_POST['email']; 
     $password = $_POST['password']; 
     $username = stripslashes($username); 
     $username = mysql_real_escape_string($username); 
     $email = stripslashes($email); 
     $email = mysql_real_escape_string($email); 
     $password = stripslashes($password); 
     $password = mysql_real_escape_string($password); 
     $trn_date = date("Y-m-d H:i:s"); 
     $query = "INSERT into `users` (username, password, email, trn_date) VALUES ('$username', '".md5($password)."', '$email', '$trn_date')"; 
     $result = mysql_query($query); 
     if (mysql_errno()) { 
      if (mysql_errno()==1062) { 
       echo "Username already taken."; 
      } 
     }else{ 
      if($result){ 
      echo "You are registered successfully.</h3><br/>Click here to <a href='login.php'>Login</a></div>"; 
     } 
     } 
    }else{ 
?> 

希望這對你的作品的評論代碼....

Answer 2

最好的辦法是在你的數據庫中設置用戶名爲主鍵，它會給你重複的錯誤。

回答你問你的代碼，將搜索用戶名，如果存在，不要添加。

無論如何，你的問題是重複的。 Here

Answer 3

檢查唯一性的最佳方法是，您必須將用戶名設置爲數據庫中的主鍵，但是如果要手動檢查，然後使用select查詢來檢查該用戶名是否已存在於數據庫中？

 <?php 
      require('db.php'); 
      // If form submitted, insert values into the database. 
      if (isset($_POST['username'])){ 
       $username = $_POST['username']; 
       $email = $_POST['email']; 
       $password = $_POST['password']; 
       $username = stripslashes($username); 
       $username = mysql_real_escape_string($username); 
       $email = stripslashes($email); 
       $email = mysql_real_escape_string($email); 
       $password = stripslashes($password); 
       $password = mysql_real_escape_string($password); 
       $trn_date = date("Y-m-d H:i:s"); 

       $res_login = mysql_query("select * from users where username='$username'"); 
       $sql_num = mysql_num_rows($res_login); 
       if($sql_num > 0) 
       { 
         echo "Username is already exists please try with another username"; 
       } 
       else 
       { 
         $query = "INSERT into `users` (username, password, email, trn_date) VALUES ('$username', '".md5($password)."', '$email', '$trn_date')"; 
         $result = mysql_query($query); 
         if($result) 
         { 
            echo "You are registered successfully.</h3><br/>Click here to <a href='login.php'>Login</a></div>"; 
         } 
         else 
         { 
            echo "error in registration"; 
         } 
       } 
     } 
     ?> 

請使用準備好的語句進行最佳編程練習。訪問此鏈接： PDO::prepare manual