What is PDO (PHP Data Objects) ?

 PDO: A Versatile PHP Database Abstraction Layer

PDO (PHP Data Objects) is a database abstraction layer that provides a consistent way to interact with various database systems, such as MySQL, PostgreSQL, SQLite, and more. By using PDO, you can write database-agnostic code, making your applications more flexible and portable.

Key Benefits of Using PDO:

• Consistent API: Offers a unified API for different database systems, simplifying database operations.
• Prepared Statements: Helps prevent SQL injection attacks by pre-compiling SQL statements.
• Error Handling: Provides robust error handling mechanisms to identify and address database issues.
• Transactions: Supports transactions for reliable data integrity.
• Fetch Modes: Offers flexible ways to fetch data, including associative arrays, numeric arrays, and objects.

Basic Usage:

1. Connect to a Database:

   PHP

   $dsn = 'mysql:host=localhost;dbname=my_database';
   $username = 'user';
   $password = 'password';
   
   try {
       $pdo = new PDO($dsn, $username, $password);
   } catch (PDOException $e) {
       echo 'Connection failed: ' . $e->getMessage();
   }
   

2. Prepare and Execute Statements:

   PHP

   $stmt = $pdo->prepare('SELECT * FROM users WHERE id = :id');
   $stmt->bindParam(':id', $userId);
   $userId = 10;
   $stmt->execute();
   
   // Fetch data
   $row = $stmt->fetch(PDO::FETCH_ASSOC);
   

3. Error Handling:

   PHP

   if ($stmt->errorCode() != 0) {
       $errorInfo = $stmt->errorInfo();
       echo 'Error: ' . $errorInfo[2];
   }
   

Advanced Usage:

• Transactions:
  PHP

  $pdo->beginTransaction();
  // ... SQL statements ...
  $pdo->commit(); // Or $pdo->rollBack();
  

• Fetch Modes:
  PHP

  // Fetch all rows as an associative array
  $rows = $stmt->fetchAll(PDO::FETCH_ASSOC);
  
  // Fetch a single row as an object
  $row = $stmt->fetchObject();
  

• Prepared Statements with Multiple Parameters:
  PHP

  $stmt = $pdo->prepare('INSERT INTO users (name, email) VALUES (:name, :email)');
  $stmt->bindParam(':name', $name);
  $stmt->bindParam(':email', $email);
  // ...
  $stmt->execute();
  

Remember:

• Always use prepared statements to prevent SQL injection.
• Close database connections when you're done to release resources.
• Consider using PDO's error handling mechanisms to catch and handle exceptions.
• For more complex operations, refer to the official PDO documentation.

By following these guidelines and leveraging the power of PDO, you can write secure, efficient, and maintainable PHP database applications.