Using PHP to Investigate Database File Organization: Understanding B and B+ Trees

I'm learning about database management systems (DBMS) and PHP, with a special focus on file organization utilizing B and B+ trees. While I'm making progress, I'm hitting some barriers and could need your help to get past them.

// PHP snippet interacting with a database using B and B+ trees <?php // Code logic involving database operations with B and B+ trees ?>

I'm not looking for a quick fix; I want to learn how file organization using B and B+ trees interacts with PHP and database administration. Can you explain how PHP interacts with these file formats in a database context? Furthermore, the source of that is here. Any advise or best practices for successfully leveraging B and B+ trees in combination with PHP for data organizing would be highly appreciated.
Your ideas and examples, suited to the combination of PHP and database file management, would be quite useful in my learning path. Let's work together to understand the complexity of file structure in databases utilizing B and B+ trees in the PHP environment!