PDO, or PHP Data Objects, is a database access layer providing a uniform method of access to multiple databases. Unlike older PHP database extensions like mysqli, PDO is a more abstract data-access layer, meaning it can work with multiple database systems without requiring a different set of functions for each. PDO provides a consistent API for accessing several different types of databases, offering prepared statements and stored procedures, which enhances security by preventing SQL injection attacks. It's widely favored for its flexibility and database-agnostic nature in PHP development.
