But work.like_query.count() will be efficient if you have the right indexes in the database, no?
I think if you want to denormalize that count all the way and also stay very efficient, maybe it would be good to do it right on the db server with a trigger and a stored procedure and avoid extra python function calls. What database do you use? On Wednesday, December 5, 2012 3:06:03 PM UTC-8, Hong Minhee wrote: > > Hi, > > I am making a typical web application using SQLAlchemy, and it contains > “users”, “works” and “likes”: > > > - users ( id, login, … ) > - works ( id, title, … ) > - likes ( user_id, work_id ) > > > I want to print how many users liked each work, so the most simple (but > naive) is querying count of them e.g.: > > len(work.like_set) > work.like_query.count() > > > However it’s inefficient, so I want to maintain like_count field or such > thing for works. The problem is that I have to manually update the field > every time new like is inserted or existing like is deleted. I thought it > could be automatically updated without inconsistency if I catch SQLAlchemy > events, but I’m not sure whether it’s correct way to do it or not. > > How do you guys solve such situation with SQLAlchemy? > > Thanks, > Hong Minhee > -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To view this discussion on the web visit https://groups.google.com/d/msg/sqlalchemy/-/1bSJm_qJci8J. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
