What? You don't keep the objects permanently in memory. You call up the faculty object via ORM, perform your action such deleting a student. Then get rid of the facaulity object(Going out scope in the method). Next to you call up the faculty object via orm everything's updated.

"Then I want to be able to filter students according to different conditions. And I end up writing nested loops for every possible condition and join I need. I refactor. I generalize. After a few months or years I've implemented nonstandard relational database."

Only a moron would write loops to search using an ORM. You implement a generic search method on the object, which executes the relevant SQL statement(Via HQL or LINQ) and returns the result. ORMS do this stuff automatically, no need to write loops to search...

I mean how badly have you been abusing ORMS?

You've been using ORMS wrong. ORMS provide the whole range relational features. They just map the results of the SQL statement into objects.

Relational Databases are good keeping data integrity correct, not so good at modelling computations. So you use the best tool for the job, relational database for storing data. Then extract that data from the database, and then use whatever (functional, OO, logic languages) to perform operations on that data.

Relational is not a way to perform computations on data, other than searching and using the various relational search features. Try implementing a machine learning algo on data using solely SQL...