One of the most important developments in the PHP world was the backward compatibility break for the PHP MySQL extension, which leaves us with two methods to connect to the database: MySQLi and PDO.
In PHP 7, the MySQL extension is completely removed. Thus, in this article, I will discuss how to convert a MySQL extension into MySQLi. The first thing you should understand is that MySQL works as a resource whereas MySQLi works as a resource and an object. While you really do not need to know the technical differences, you must understand that these two are a lot different from each other.