Entity Relational Mapping https://www.doctrine-project.org/projects/doctrine-orm/en/3.3/reference/association-mapping.html#many-to-many-bidirectional https://learn.microsoft.com/en-us/ef/core/modeling/relationships https://www.learnentityframeworkcore.com/relationships https://entityframework-extensions.net/bulk-extensions https://www.cdata.com/ https://www.npgsql.org/index.html