Just FYI: the database software is called MySQL. MySQLi is a PHP module you can use to connect to a MySQL database server. PDO is another PHP module, which provides a generic interface to interact with databases, which also supports MySQL.
MySQLi and PDO are both valid ways to connect to a MySQL database. It’s personal preference which one you choose to use.
As for the issue itself, I’m very curious as to whether the query runs successfully or not. The $statement->execute() function should return either a TRUE or FALSE value, depending on whether the query was successful.
Does the query return successfully or not?
If it doesn’t, you can enable display_errors in the Alter PHP Config menu in your control panel to show the error messages being generated from the query.