PHP连接到mysql数据库 [英] PHP connect to mysql database

问题描述

我试图在我的数据库和我在网站上使用的登录表单之间建立连接，但是我面临着一个问题，所以每次点击登录时，都会显示No数据库选择

这是我的代码：

 < php 
 session_start（）; $（$ _ POST ['Email']）&& isset（$ _ POST ['Username']）&& isset（$ _ POST ['Password']））$ 
 
 b $ b {
 $ mysql_hostname =localhost; 
 $ mysql_user =root; 
 $ mysql_password =; 
 $ mysql_database =db_3300; 
 
 $ con = mysql_connect（$ mysql_hostname，$ mysql_user，$ mysql_password，$ mysql_database）; 
 
 //检查连接
 if（！$ con）
 {
 die（'Could not connect：'。mysql_error（））; 
 
 $ b $ result = mysql_query（SELECT * FROM users where 
 Username ='。$ _ POST ['Username']。''
 AND Email = ''。$ _ POST ['Email']。'
 AND Password ='。$ _ POST ['Password']。'）
或者die（mysql_error（））; 
 
 
 while（$ row = mysql_fetch_array（$ result））
 {echo $ result; 
回声您已成功连接; 
 $ _SESSION [authenticated] = true; 
出口; 
} 
 
 mysql_close（$ con）; 
} 
？> 
  

我希望有人能帮助我。

在您的 > $ con

  $ con = mysql_connect（$ mysql_hostname，$ mysql_user，$ mysql_password）; //从这里删除$ mysql_database 
 $ db_selected = mysql_select_db（$ mysql_database，$ con）; //添加了这个$​​ b $ b  

^{另外，你正在使用mysql_ *函数，即将推出的PHP版本。切换到mysqli_ *或PDO。}

I'm trying to make a connection between my database and the login form that I'm using in my website, but I'm facing a problem with that, so every time I click on login, this message appears "No database selected"

Here is my code:

<?php
session_start();

if(isset($_POST['Email']) && isset($_POST['Username']) && isset($_POST['Password']))
{
    $mysql_hostname = "localhost";
    $mysql_user = "root";
    $mysql_password = "";
    $mysql_database = "db_3300";

    $con=mysql_connect($mysql_hostname, $mysql_user, $mysql_password, $mysql_database);

    // Check connection
    if (!$con)
    {
        die('Could not connect: ' . mysql_error());
    }

    $result = mysql_query("SELECT * FROM users where
    Username='".$_POST['Username']."'
    AND Email ='".$_POST['Email']."'
    AND Password ='".$_POST['Password']."'")
    or die (mysql_error());


    while($row = mysql_fetch_array($result))
    { echo $result; 
        echo "You are successfully connected";
        $_SESSION["authenticated"] = true;
        exit;
    }

    mysql_close($con);
}
?>

I hope that someone could help me with this.

解决方案

You haven't selected your database yet.

Do this after your $con

$con=mysql_connect($mysql_hostname, $mysql_user, $mysql_password); //Removed the $mysql_database from here
$db_selected = mysql_select_db($mysql_database, $con); //Added this

^{Also, You are using mysql_* functions which will be deprecated in the coming versions of PHP. Switch to mysqli_* or PDO Instead.}

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