Django ORM internals

[Mahdi Xareie]

Hello everyone,

I got interested in contributing to the django project recently and I
noticed lots of tickets are related to the ORM, so it seems to me,
contributing to the ORM is very valuable at moment.
I started to read OMR related tickets and also checking related pull
requests, but since ORM is a big package and contains lots of modules, 
I found it very difficult to understand the changes in the pull requests.
Do you know any good resource about the internal structure of the django
ORM? a blog post perhaps, anythong to help me get started on the ORM
internals.

Thank you very much