PHP and Cassandra database applications

With the continuous development of Internet technology, the functions and scale of Web applications continue to grow, and the requirements for database access are also getting higher and higher. This has prompted developers to look for new database solutions to improve the performance and scalability of web applications. This article will introduce how to use the PHP language and Cassandra database to build high-performance, scalable web applications.

1. What is Cassandra database

Cassandra is an open source distributed NoSQL database system, originally developed by Facebook and now maintained by the Apache Foundation. Its concept is to take into account data availability, scalability and fault tolerance while ensuring high performance.

The characteristics of the Cassandra database include:

1. Distributed storage: Cassandra uses distributed storage, and the data will be stored on multiple nodes to ensure that the data between each node Redundant backup improves reliability and availability.
2. Column storage: Cassandra uses column storage and stores each row of data as a "column family" for greater flexibility.
3. Data consistency: Cassandra provides high availability and data recovery through automatic data replication within the cluster, and can achieve different performance requirements through adjustable consistency levels.
4. Scalability: Cassandra supports dynamic node addition and removal, and can efficiently expand horizontally.
5. High performance: Cassandra improves read and write performance through asynchronous writing and indexing, while improving concurrency through load balancing strategies.

2. PHP connects to Cassandra database

Cassandra database supports a variety of client APIs, among which PHP and CQL statements are one of the most convenient ways. CQL is the abbreviation of Cassandra Query Language, which is similar to SQL, but has richer data types and supports complex distributed query operations.

Below we use PHP's cassandra-driver to connect and operate the Cassandra database.

1. Installing cassandra-driver

PHP’s cassandra-driver can be installed through composer. Open the command line, enter your project root directory, and run the following command:

composer require datastax/php-driver

2. Connect to Cassandra

To connect to Cassandra, you need to know the host and port number to connect to. Here is one Sample code for connecting to Cassandra:

<?php
//连接Cassandra
$cluster = Cassandra::cluster()
    ->withContactPoints('127.0.0.1')
    ->withPort(9042)
    ->build();
$session = $cluster->connect();
?>

The above code creates a Cassandra service connection point through the cluster() method and connects to it through the connect() method. Among them, 127.0.0.1 indicates the IP address of the Cassandra service, and 9042 indicates the Cassandra service port number.

3. Execute CQL statements

CQL statements are used to interact with the Cassandra database. You can easily execute CQL statements using PHP's cassandra-driver. The following is a sample code for executing a CQL statement:

<?php
//执行CQL语句
$cql = "SELECT * FROM mykeyspace.mytable WHERE id='123'";
$statement = new CassandraSimpleStatement($cql);
$result = $session->execute($statement);
?>

The above code uses the SimpleStatement class to create a CQL query statement, then uses the execute() method to execute the statement, and save the query results in the $result variable.

4. Insert data

Cassandra database supports inserting JSON format data with high flexibility. The following is a sample code:

<?php
//插入数据
$cql = "INSERT INTO mykeyspace.mytable JSON '{"id": "123", "name": "Tom", "age": 18}'";
$statement = new CassandraSimpleStatement($cql);
$session->execute($statement);
?>

The above code defines a JSON format data and inserts it into the mykeyspace.mytable table through CQL statements.

3. Application Example

Below we combine a simple web application to demonstrate how to use PHP and Cassandra database to build high-performance, scalable applications. This sample application provides login and registration functionality and uses a Cassandra database to store user information.

1. Create Cassandra table

First, we need to create a table in the Cassandra database to store user information. The following is an example CQL statement:

CREATE KEYSPACE mykeyspace WITH replication = {'class': 'SimpleStrategy', 'replication_factor': '1'}  AND durable_writes = true;

CREATE TABLE mykeyspace.users (
    id text PRIMARY KEY,
    username text,
    email text,
    password text
);

The above code creates a keyspace named "mykeyspace" and creates a table named "users" in it. The table contains 4 columns, namely id, username, email and password, where id is the primary key.

2. Implementing user registration function

The following is a sample code for a user registration page:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>User Registration</title>
</head>
<body>
    <h2 id="User-Registration">User Registration</h2>
    <form method="post" action="register.php">
        <label for="username">Username:</label>
        <input type="text" name="username" id="username"><br>
        <label for="email">Email:</label>
        <input type="email" name="email" id="email"><br>
        <label for="password">Password:</label>
        <input type="password" name="password" id="password"><br>
        <input type="submit" name="submit" value="Register">
    </form>
</body>
</html>

The above code creates an input box with 3 input boxes Registration form, in which username, email and password are required.

Then, we need to write PHP code in the register.php file to store user registration information in the Cassandra database:

<?php
//连接Cassandra
$cluster = Cassandra::cluster()
    ->withContactPoints('127.0.0.1')
    ->withPort(9042)
    ->build();
$session = $cluster->connect();

//获取表单数据
$username = $_POST['username'];
$email = $_POST['email'];
$password = $_POST['password'];

//生成一个唯一的ID
$id = uniqid();

//将注册信息插入到Cassandra表中
$cql = "INSERT INTO mykeyspace.users (id, username, email, password) VALUES (?, ?, ?, ?)";
$statement = new CassandraSimpleStatement($cql);
$session->execute($statement, array($id, $username, $email, $password));

//跳转到登录页面
header('Location: login.php');
?>

The above code gets the data submitted from the form and generates a unique ID. Then insert the user information into the Cassandra table and jump to the login page.

3. Implement user login function

The following is a sample code for a user login page:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>User Login</title>
</head>
<body>
    <h2 id="User-Login">User Login</h2>
    <form method="post" action="login.php">
        <label for="username">Username:</label>
        <input type="text" name="username" id="username"><br>
        <label for="password">Password:</label>
        <input type="password" name="password" id="password"><br>
        <input type="submit" name="submit" value="Login">
    </form>
</body>
</html>

The above code creates an input box with 2 input boxes login form.

Then, we need to write PHP code in the login.php file to verify the user login information in the Cassandra database:

<?php
//连接Cassandra
$cluster = Cassandra::cluster()
    ->withContactPoints('127.0.0.1')
    ->withPort(9042)
    ->build();
$session = $cluster->connect();

//获取表单数据
$username = $_POST['username'];
$password = $_POST['password'];

//查询用户信息
$cql = "SELECT * FROM mykeyspace.users WHERE username=? AND password=?";
$statement = new CassandraSimpleStatement($cql);
$result = $session->execute($statement, array($username, $password));

//验证用户信息
if (count($result) > 0) {
    //登录成功
    header('Location: home.php');
} else {
    //登录失败
    echo 'Login failed.';
}
?>

The above code gets the username and password from the form submission and passes it through CQL Statement to query user information from Cassandra table. If the query result is not empty, the login is successful; otherwise, the login fails.

4. Summary

Cassandra database is an excellent NoSQL database system with high performance, scalability, fault tolerance and data consistency, and is suitable for handling the access requirements of large-scale web applications. PHP's cassandra-driver provides an API to connect to and operate the Cassandra database, making it easy to develop high-performance, scalable web applications. This article demonstrates how to use PHP and Cassandra database to build a simple user registration and login system through a sample program, hoping to provide some reference for developers.

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