How to create a user login system using PHP and SQLite

How to create a user login system using PHP and SQLite

In today's Internet era, the user login system is one of the basic functions of many websites and applications. This article will introduce how to create a simple and powerful user login system using PHP and SQLite. SQLite is an embedded database engine. It is a zero-configuration, server-side database engine. PHP is a popular server-side scripting language that can be used in conjunction with SQLite to create a flexible and efficient user login system.

With the following steps, you can start creating a user login system using PHP and SQLite.

Step 1: Set up the database connection

First, you need to create a SQLite database and establish a connection to the database. You can use SQLite's PHP extension library to perform these tasks. Here is a sample code for connecting to a SQLite database:

<?php
$db = new SQLite3('database.db');
if(!$db){
  die($db->lastErrorMsg());
}
?>

In this example, we create a database called 'database.db' and then use the SQLite3 class Constructor and the path to the database file to create a database connection. If the connection fails, an error message will be printed.

Step 2: Create a user table

Next, you need to create a user table to store the user's information, such as username and password. Below is a sample code to create a users table:

<?php
$query = "CREATE TABLE IF NOT EXISTS users (
        id INTEGER PRIMARY KEY AUTOINCREMENT,
        username TEXT NOT NULL,
        password TEXT NOT NULL
    )";

$result = $db->exec($query);

if(!$result){
    die($db->lastErrorMsg());
}
?>

In this example, we have created a table named 'users' using SQL statements. The 'id' column is the primary key, which will be automatically incremented; the 'username' and 'password' columns are used to store the user's username and password.

Step 3: Create the registration function

Now you can create a registration interface that allows users to enter their username and password and save it to the user table. Here is a sample code that handles a registration request:

<?php
if(isset($_POST['submit'])){
    $username = $_POST['username'];
    $password = $_POST['password'];

    $query = "INSERT INTO users (username, password) VALUES ('$username', '$password')";

    $result = $db->exec($query);

    if(!$result){
        die($db->lastErrorMsg());
    } else {
        echo "User registered successfully!";
    }
}
?>

In this example, we use the $_POST superglobal variable to get the username and password submitted by the user. We then use SQL statements to insert the username and password into the users table.

Step 4: Create the login function

Now you can create a login interface that allows the user to enter a username and password and match it with the user information in the database. Here is a sample code to handle a login request:

<?php
if(isset($_POST['submit'])){
    $username = $_POST['username'];
    $password = $_POST['password'];

    $query = "SELECT * FROM users WHERE username='$username' AND password='$password'";

    $result = $db->query($query);

    if($result->fetchArray()){
        echo "Login successful!";
    } else {
        echo "Invalid username or password!";
    }
}
?>

In this example, we use the $_POST superglobal variable to get the username and password submitted by the user. We then use a SQL statement to query the users table with the corresponding username and password. If the query result is not empty, it means the login is successful, otherwise it means the username or password is invalid.

At this point, you have completed the basic steps of creating a user login system using PHP and SQLite. However, this is just a simple example and you can extend the system with more functionality based on your needs.

Summary

This article introduces how to use PHP and SQLite to create a user login system. By setting up a database connection, creating a user table, creating a registration function, and creating a login function, you can create a simple yet powerful user login system. Of course, this is just a basic example and you can extend it with more functionality according to your needs. Hopefully this article will help you get started creating your own user login system!

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