To connect to a database, there are two ways to PHP: MySQLi and PDO. 1. MySQLi is simple and direct, suitable for projects that only use MySQL, supports process-oriented and object-oriented writing, and it is recommended to use object methods to obtain a clearer structure; 2. PDO is more flexible, supports multiple databases, suitable for projects that may migrate databases or require unified interfaces, has preprocessing statements to prevent SQL injection, and provides a unified error handling mechanism. Choosing MySQLi allows for a cleaner API and slightly higher performance, and choosing PDO provides improved scalability and security. Both need to be paid attention to correct configuration, error handling and connection closure.

To connect to a database, PHP provides two common ways: MySQLi and PDO. They all complete tasks, but each has its own characteristics. If you need simple and direct operations, MySQLi is a good choice; if you want a more flexible way to support more database types, PDO is more suitable.

Connecting to a database using MySQLi

MySQLi is a built-in extension in PHP, designed for interaction with MySQL databases. It supports two types of writing methods: process-oriented and object-oriented. It is recommended to use object-oriented method, and the structure is clearer.

Basic connection example:

 $host = 'localhost';
$username = 'your_username';
$password = 'your_password';
$database = 'your_database';

$conn = new mysqli($host, $username, $password, $database);

if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

Note:

• Make sure the database username, password, and database name are correct.
• If the connection fails, remember to use die() or log to handle the error to avoid blank pages or user confusion.
• Remember to close the connection after the operation is completed: $conn->close();

Connecting to a database using PDO

PDO (PHP Data Objects) is a more general way, supporting multiple database systems (such as MySQL, PostgreSQL, SQLite, etc.), suitable for the situation where the project may migrate the database.

Basic connection example:

 $host = 'localhost';
$dbname = 'your_database';
$user = 'your_username';
$pass = 'your_password';

try {
    $pdo = new PDO("mysql:host=$host;dbname=$dbname", $user, $pass);
    // Set the error mode to exception $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch (PDOException $e) {
    die("Connection failed:" . $e->getMessage());
}

Advantages description:

• Supports preprocessing statements to effectively prevent SQL injection.
• Error handling is more unified, and can be managed centrally by setting properties.
• It is more suitable for future expansions, such as small code changes when switching from MySQL to other databases.

Choose MySQLi or PDO?

It depends on your project requirements:

• ?Choose MySQLi if:

  • The project only uses MySQL and does not need to be compatible with other databases.
  • I prefer a concise API and don't want to learn too many abstract concepts.
  • The performance requirements are high. Although there is not much difference, MySQLi is slightly faster.

• ?PDO if:

  • It may be migrated to another database, such as PostgreSQL.
  • A unified interface is required to process different data sources.
  • Want to use preprocessing statements to enhance security.

Both can complete the database connection task well, the key is to look at the long-term planning of the project and personal habits.

Basically that's it. Connecting to the database is not complicated, but it is easy to ignore error handling and security settings. It is recommended to add error prompts and appropriate configuration from the beginning.

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