连接一个php页面到mySql

Question

我有一个问题连接任何php页面到MySQL，我是新手php，我尝试了所有我能在网上找到的，但没有一个有效。我试着下载了一个php表单，并为这个页面创建了一个数据库，但它仍然没有向数据库添加任何东西。

<html>

<link href="//db.onlinewebfonts.com/c/a4e256ed67403c6ad5d43937ed48a77b?family=Core+Sans+N+W01+35+Light" rel="stylesheet" type="text/css"/>
<link rel="stylesheet" href="form.css" type="text/css">
<div class="body-content">
  <div class="module">
    <h1>Create an account</h1>

    <?php
session_start();
$_SESSION['message'] = '';
$mysqli = new mysqli("127.0.0.1", "root", "", "accounts_complete");

//the form has been submitted with post
if ($_SERVER["REQUEST_METHOD"] == "POST") {

    //two passwords are equal to each other
    if ($_POST['password'] == $_POST['confirmpassword']) {

        //set all the post variables
        $username = $mysqli_real_escape_string($_POST['username']);
        $email = $mysqli_real_escape_string($_POST['email']);
        $password = md5($_POST['password']); //md5 has password for security
        $avatar_path = $mysqli_real_escape_string('images/'.$_FILES['avatar']['name']);

        //make sure the file type is image
        if (preg_match("!image!",$_FILES['avatar']['type'])) {

            //copy image to images/ folder 
            if (copy($_FILES['avatar']['tmp_name'], $avatar_path)){

                //set session variables
                $_SESSION['username'] = $username;
                $_SESSION['avatar'] = $avatar_path;

                //insert user data into database
                $sql = "INSERT INTO users (username, email, password, avatar) "
                        . "VALUES ('$username', '$email', '$password', '$avatar_path')";

                //if the query is successsful, redirect to welcome.php page, done!
                if ($mysqli_query($sql) === true){
                    $_SESSION['message'] = "Registration succesful! Added $username to the database!";
                    header("location: welcome.php");
                }
                else {
                    $_SESSION['message'] = 'User could not be added to the database!';
                }
                $mysqli_close();          
            }
            else {
                $_SESSION['message'] = 'File upload failed!';
            }
        }
        else {
            $_SESSION['message'] = 'Please only upload GIF, JPG or PNG images!';
        }
    }
    else {
        $_SESSION['message'] = 'Two passwords do not match!';
    }
}
?>


    <form class="form" action="form.php" method="post" enctype="multipart/form-data" autocomplete="off">
      <div class="alert alert-error"><?= $_SESSION['message'] ?></div>
      <input type="text" placeholder="User Name" name="username" required />
      <input type="email" placeholder="Email" name="email" required />
      <input type="password" placeholder="Password" name="password" autocomplete="new-password" required />
      <input type="password" placeholder="Confirm Password" name="confirmpassword" autocomplete="new-password" required />
      <div class="avatar"><label>Select your avatar: </label><input type="file" name="avatar" accept="image/*" required /></div>
      <input type="submit" value="Register" name="register" class="btn btn-block btn-primary" />
    </form>
  </div>
</div>
</html>

密码为空，因为没有任何密码。你能帮帮我吗?提前谢谢。

Answer 1

实际上有很多错误，但基于关于数据库的问题：

1. mysqli_语法是一个函数，而不是一个变量。因此，您只需删除任何初始$ at mysqli_语法。
2. 在mysqli，您需要将连接变量传递给mysqli_函数的第一个参数。

示例：

之前：$mysqli_query($sql);

之后：mysqli_query($mysqli, $sql)

和

之前：$mysqli_close();

之后：mysqli_close($mysqli)