When it comes to working with MySQL databases in your web applications, you have several options. Two of the most commonly used options are MySQL (the original MySQL extension) and MySQLi (short for MySQL Improved). Both of these extensions allow PHP developers to interact with MySQL databases, but they have some notable differences. In this article, we will explore the distinctions between MySQL and MySQLi and help you decide which one is the right choice for your project.

MySQL Extension (mysql):

The MySQL extension, often referred to as the "mysql" extension, was the original MySQL extension for PHP. It has been available since PHP 2.0 and has been widely used in countless web applications. Here are some key characteristics of the MySQL extension:

1. Procedural API: The MySQL extension primarily offers a procedural API, which means you interact with the database using functions like mysql_connect() and mysql_query().

2. Limited Functionality: The MySQL extension provides basic database interaction capabilities but lacks advanced features and security enhancements.

3. Deprecated: As of PHP 5.5.0, the MySQL extension has been deprecated, and it is strongly discouraged to use it in new projects. It has also been removed entirely in PHP 7.

MySQLi Extension (mysqli):

The MySQL Improved extension, commonly referred to as "MySQLi," was introduced to address the limitations of the original MySQL extension. It is specifically designed to provide a more powerful and secure way to interact with MySQL databases. Here are some key characteristics of the MySQLi extension:

1. Procedural and Object-Oriented APIs: MySQLi offers both procedural and object-oriented APIs, giving developers the flexibility to choose their preferred coding style. The procedural API is similar to the one used in the original MySQL extension, making it easier for developers to transition.

2. Enhanced Functionality: MySQLi provides a wide range of features, including support for prepared statements, transactions, and stored procedures. Prepared statements are particularly valuable for preventing SQL injection attacks.

3. Security Enhancements: MySQLi includes security improvements, making it a safer choice for database interactions. Prepared statements, in particular, help mitigate the risk of SQL injection vulnerabilities.

4. Active Development: Unlike the original MySQL extension, MySQLi is actively maintained and updated, ensuring compatibility with the latest MySQL server versions and PHP releases.

Which Version Should You Use?

Given that the original MySQL extension is deprecated and removed in PHP 7, it is strongly recommended to use the MySQLi extension for any new PHP projects or when upgrading existing ones. Here are some reasons why you should choose MySQLi:

1. Security: MySQLi offers improved security features, including prepared statements, which can help prevent SQL injection attacks.

2. Advanced Functionality: MySQLi provides a broader range of functionality, making it suitable for a wide variety of database interactions, from basic queries to complex transactions.

3. Compatibility: MySQLi is compatible with the latest MySQL server versions and PHP releases, ensuring long-term support and compatibility.

4. Active Development: The fact that MySQLi is actively developed means that any issues or bugs are more likely to be addressed promptly.

In conclusion, while the original MySQL extension has been widely used in the past, it is no longer a recommended choice for new projects or when upgrading existing ones. MySQLi offers enhanced functionality, security, and compatibility, making it the preferred option for working with MySQL databases in PHP applications. Whether you opt for the procedural or object-oriented API within MySQLi, you'll have access to a robust and secure set of tools for interacting with MySQL databases.