What is the primary advantage of using PDO in PHP?

The primary advantage of using PDO (PHP Data Objects) in PHP is that it provides a uniform method of access to multiple databases. This means that developers can write their database interaction code in a way that is consistent regardless of the database management system (DBMS) in use, whether it's MySQL, PostgreSQL, SQLite, or others. By using PDO, one can switch between different databases simply by changing the connection string, without needing to rewrite the database interaction code. This flexibility makes it easier to maintain applications that may need to work with different databases over time or across different environments.

While aspects like protection against SQL injection are important and PDO does offer prepared statements which aid in this protection, the core benefit of PDO lies in its ability to abstract database access across various systems. Other options, such as support for only MySQL or requiring no server configuration, do not accurately represent the advantages of using PDO. In fact, PDO is designed explicitly to work with multiple databases and requires standard server configuration for any of the supported systems.