Explore Doctrine relationships in Symfony 5 Framework through a comprehensive tutorial covering One-to-One, One-to-Many, and Many-to-Many relationships, as well as more advanced concepts. Dive into Object Relational Mapping (ORM) using Doctrine, which simplifies database interactions for MySQL, PostgreSQL, and Oracle. Learn to write Object-Oriented PHP without focusing on underlying database tables. Begin with an empty MySQL8 database and Symfony 5 project served on Nginx, with instructions provided for setting up the environment using Docker. Cover topics including bidirectional and unidirectional relationships, self-joining relationships, cascade persist, and handling extra fields in Many-to-Many relationships. Gain insights into quickly installing Symfony on various operating systems and optimizing your development workflow with PhpStorm tips and tricks.