How to use PHP to perform database operations in a Linux environment

In modern web applications, the database is an essential component. PHP is a popular server-side scripting language that can interact with various databases. This article will introduce how to use PHP scripts for database operations in a Linux environment and provide some specific code examples.

Step 1: Install the necessary software and dependencies
Before we begin, we need to ensure that PHP and related dependencies are installed in the Linux environment. Typically, we need to install PHP, a database server (such as MySQL or PostgreSQL), appropriate PHP extensions (such as mysqli or PDO), and other necessary software packages. You can install these software and dependencies by running the following command:

sudo apt-get install php
sudo apt-get install mysql-server
sudo apt-get install php-mysql

Step 2: Connect to the database
To interact with the database using PHP, we first need to establish a database connection in a PHP script. For MySQL database, we can use the mysqli extension to implement the connection. The following is a sample code to connect to a MySQL database:

<?php
$servername = "localhost";
$username = "root";
$password = "password";
$dbname = "mydatabase";

// 創(chuàng)建連接
$conn = new mysqli($servername, $username, $password, $dbname);

// 檢測連接是否成功
if ($conn->connect_error) {
    die("連接失敗: " . $conn->connect_error);
}

echo "連接成功";
?>

Please note that you need to replace $servername, $username, $password Replace $dbname with your own database information.

Step 3: Execute SQL queries
Once connected to the database, we can use PHP to perform various SQL queries and operations. The following are some common examples:

a. Query data
To query data in the database, we can use the SELECT statement. The following is a simple example:

<?php
$sql = "SELECT * FROM users";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {
        echo "id: " . $row["id"]. " - 姓名: " . $row["name"]. "<br>";
    }
} else {
    echo "0 結(jié)果";
}

$conn->close();
?>

b. Insert data
To insert data into the database, we can use the INSERT statement. The following is a simple example:

<?php
$sql = "INSERT INTO users (name, email) VALUES ('John Doe', 'john@example.com')";

if ($conn->query($sql) === TRUE) {
    echo "新記錄插入成功";
} else {
    echo "Error: " . $sql . "<br>" . $conn->error;
}

$conn->close();
?>

c. Update data
To update data in the database, we can use the UPDATE statement. The following is a simple example:

<?php
$sql = "UPDATE users SET email='johndoe@example.com' WHERE id=1";

if ($conn->query($sql) === TRUE) {
    echo "記錄更新成功";
} else {
    echo "Error: " . $sql . "<br>" . $conn->error;
}

$conn->close();
?>

d. Delete data
To delete data in the database, we can use the DELETE statement. The following is a simple example:

<?php
$sql = "DELETE FROM users WHERE id=1";

if ($conn->query($sql) === TRUE) {
    echo "記錄刪除成功";
} else {
    echo "Error: " . $sql . "<br>" . $conn->error;
}

$conn->close();
?>

Summary
Using PHP to perform database operations in a Linux environment is relatively simple. After connecting to the database, we can perform various SQL queries and operations. In this article, we provide some common sample code, including querying data, inserting data, updating data, and deleting data. These sample codes will help you better understand how to use PHP for database operations in a Linux environment.

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