How to serialize and deserialize Django ORM query (not queryset)?
According to your answer, 

User passes some content-specific parameters into a form, then view function, that recieves POST, constructs query

one option is to store parameters (pickle'd or json'ed, or in a model) and reconstruct query with regular django means. This is somewhat more robust solution, since it can handle some datastructure changes.
My use case is that I need to store queries in DB and retrieve them from time to time and evaluate. Thats needed for mailing-app where every user can subscribe to a web-site content selected by individually customized query.
Most basic solution is to store raw SQL and use it with RawQuerySet. But I wonder is there better solutions?