How to implement simple registration and login system in php

PHP is a server-side scripting language originally developed for website design. With the popularity of the Internet, PHP has become one of the mainstream languages ​​​​for website development. Among them, the registration and login system is one of the most basic and commonly used functions in website development. This article will use PHP as the main development language to introduce how to implement a simple registration and login system.

1. Registration system

1.1. Requirements analysis

Before developing a registration system, it is necessary to analyze the requirements first. The main functions required by the registration system include: user registration, user login, user name and password verification, user information storage, etc.

1.2. Database design

In order to store user information, a user table needs to be created in the database. This table needs to contain information such as the user's ID, username, and password. Among them, the user's ID should be set to an auto-increasing type to facilitate subsequent operations.

1.3. Registration page

The registration page needs to contain an input box and a submit button. The user enters his or her user name and password in the input box and submits it to the server for processing.

1.4. Registration processing

After the user clicks the submit button, the user's information needs to be saved in the database. At the same time, it is also necessary to verify the information entered by the user to ensure that the entered information meets the specifications. If the information entered by the user is incorrect, an error message should be provided for the user to make corrections. If the information is correct, the user's information should be saved in the database and a prompt indicating successful registration should be given.

2. Login system

2.1. Requirements analysis

Logging into the system requires user name and password verification. If the information entered by the user is incorrect, the user cannot log in to the system.

2.2. Login page

The login page needs to contain an input box for username and password and a submit button. The user enters their username and password and submits it to the server for processing.

2.3. Login processing

The server needs to verify the information entered by the user and perform corresponding processing based on the verification results. If the information entered by the user is correct, the user will be redirected to the login page. If the information is incorrect, an error message should be provided for the user to make corrections.

3. PHP implementation

3.1. Database connection

In PHP, you need to use the mysqli_connect() function to connect to the MySQL database.

$db_host = "localhost";
$db_user = "root";
$db_pass = "123456";
$db_name = " test";

$conn = mysqli_connect($db_host, $db_user, $db_pass, $db_name);

if(!$conn){

die("数据库连接失败：" . mysqli_connect_error());

}

?>

In the above code, $db_host, $db_user, $db_pass and $db_name are the database address, user name, password and database name respectively. After the connection is successful, a connection object will be returned, through which the database can be operated.

3.2. User registration

The implementation code for user registration is as follows:

//Connect to the database
$conn = mysqli_connect ($db_host, $db_user, $db_pass, $db_name);

//Get the information entered by the user
$username = $_POST['username'];
$password = $_POST[ 'password'];

//Verify the information entered by the user
if(empty($username) || empty($password)){

echo "用户名和密码不能为空！";
exit;

}

//Save user information to the database
$sql = "INSERT INTO user (username, password) VALUES ('{$username}', '{$password}')";

if(mysqli_query($conn, $sql)){

echo "恭喜您，注册成功！";

}else{

echo "注册失败：" . mysqli_error($conn);

}

?>

In the above code, $username and $password are the username and password entered by the user respectively. If the entered information is empty, the user will be prompted for input.

3.3. User login

The implementation code for user login is as follows:

//Connect to the database
$conn = mysqli_connect ($db_host, $db_user, $db_pass, $db_name);

//Get the information entered by the user
$username = $_POST['username'];
$password = $_POST[ 'password'];

//Query whether the user exists in the database
$sql = "SELECT * FROM user WHERE username='{$username}' AND password='{$password}'" ;

$result = mysqli_query($conn, $sql);

if(mysqli_num_rows($result) > 0){

echo "登陆成功！";

}else{

echo "用户名或密码错误！";

}

?>

In the above code, first query the database to see if there is a record with the same user name and password as the user input. If it exists, the user will be prompted to log in successfully, otherwise the user will be prompted to enter an incorrect username or password.

4. Summary

This article introduces how to use PHP language to implement a simple registration and login system. The system has basic registration and login functions, and effectively verifies the information entered by the user. Of course, this is only a preliminary implementation, and more optimization and improvements are needed in practical applications.

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