+Forum.threads = relation(Thread, order_by=Thread.id.desc(), lazy='dynamic', backref='forum')
+
+Thread.posts = relation(Post, order_by=Post.posted_time.desc(), lazy='dynamic', backref='thread')
+Thread.first_post = relation(Post, primaryjoin=and_(Post.thread_id == Thread.id, Post.position == 1), uselist=False)
+Thread.last_post = relation(Post, primaryjoin=and_(Post.thread_id == Thread.id, Post.position == Thread.post_count), uselist=False)