select_related-like function doesn't work in RawQuerySet

I have a problem with raw sql query in Django 1.3. When I use select_related() from ORM I get whole needed data in one query.

activities = UserActivity.objects.filter(Q(user__in=friends_list),Q(activity_type = UserActivity.TYPE_POST, post__status=Post.PUBLIC_STATUS)|Q(activity_type = UserActivity.TYPE_SHORT_REVIEW)|Q(activity_type = UserActivity.TYPE_COMMENT)).select_related()

Above example give me exactly one connection to database.

[{'time': '0.164', 'sql': 'SELECT "useractivity_useractivity"."id", "useractivity_useractivity"."activity_type", "useractivity_useractivity"."status", "useractivity_useractivity"."permalink", "useractivity_useractivity"."user_id", "useractivity_useractivity"."username", "useractivity_useractivity"."object_id", "useractivity_useractivity"."watching_object_id", "useractivity_useractivity"."post_id", "useractivity_useractivity"."short_review_id", "useractivity_useractivity"."comment_id", "useractivity_useractivity"."link_id", "useractivity_useractivity"."film_id", "useractivity_useractivity"."checkin_id", "useractivity_useractivity"."title", "useractivity_useractivity"."content", "useractivity_useractivity"."film_title", "useractivity_useractivity"."film_permalink", "useractivity_useractivity"."url", "useractivity_useractivity"."url_kind", "useractivity_useractivity"."video_thumb", "useractivity_useractivity"."spoilers", "useractivity_useractivity"."is_first_post", "useractivity_useractivity"."number_of_comments", "useractivity_useractivity"."channel_name", "useractivity_useractivity"."channel_id", "useractivity_useractivity"."checkin_date", "useractivity_useractivity"."rating", "useractivity_useractivity"."featured", "useractivity_useractivity"."modified_at", "useractivity_useractivity"."created_at", "useractivity_useractivity"."LANG", "useractivity_useractivity"."is_sent", "auth_user"."id", "auth_user"."username", "auth_user"."first_name", "auth_user"."last_name", "auth_user"."email", "auth_user"."password", "auth_user"."is_staff", "auth_user"."is_active", "auth_user"."is_superuser", "auth_user"."last_login", "auth_user"."date_joined" FROM "useractivity_useractivity" INNER JOIN "auth_user" ON ("useractivity_useractivity"."user_id" = "auth_user"."id") LEFT OUTER JOIN "blog_post" ON ("useractivity_useractivity"."post_id" = "blog_post"."parent_id") LEFT OUTER JOIN "core_object" ON ("blog_post"."parent_id" = "core_object"."id") WHERE ("useractivity_useractivity"."LANG" = E\'en\'  AND "useractivity_useractivity"."user_id" IN (10, 16, 12, 14, 6, 32, 13, 40, 4, 15, 47, 5, 50, 51, 53, 33, 24, 22, 153, 208, 207, 65, 23, 398, 203, 312, 582, 402, 416, 30, 144, 979, 173, 133, 690, 1748, 38, 2104, 1918, 1989, 1850, 1788, 2389, 395, 2535, 2658, 2287, 953, 2845, 2790, 2849, 3016, 2656, 3114, 3190, 156, 2981, 3193, 2884, 193, 445, 3742, 1069, 4035, 4178, 2568, 1409, 2292, 3561, 4801, 162, 4968, 4090, 4916, 4548, 5213, 2878, 5208, 3120, 4294, 5406, 5944, 6221, 6266, 6305, 3559, 3577, 2846, 2580, 2416, 970, 6969, 7126, 7175, 6401, 5237, 172, 792, 17, 7246, 1779, 134, 6433, 3725, 6343, 2121, 4193, 721, 958, 375, 2875, 6124, 754, 137, 241, 219, 540, 337, 152, 955, 6717, 6808, 7121, 2752, 6802, 6793, 5146, 4183, 7349, 7375, 6452, 284, 6544, 4276, 7377, 7387, 151, 7314, 7357, 1373, 7397, 6260, 500, 7437, 4961, 7478, 4559, 7545, 7554, 7555, 7488, 7092, 4615, 7285, 7619, 7621, 7344, 6409, 422, 7686) AND (("core_object"."status" = 1  AND "useractivity_useractivity"."activity_type" = 1 ) OR "useractivity_useractivity"."activity_type" = 2  OR "useractivity_useractivity"."activity_type" = 3 ))'}]

But, when I try to put the same query in开发者_高级运维to raw:

activity = UserActivity.objects.raw(query)
list(activity)  

I get few thousands queries to database like:

SELECT "auth_user"."id", "auth_user"."username", "auth_user"."first_name", "auth_user"."last_name", "auth_user"."email", "auth_user"."password", "auth_user"."is_staff", "auth_user"."is_active", "auth_user"."is_superuser", "auth_user"."last_login", "auth_user"."date_joined" FROM "auth_user" WHERE "auth_user"."id" = 4801    

It looks like RawQuerySet doesn't fetch all data in one execution, but every time when friends_list is called, database is queried about user priviledges.

Why RawQuerySet doesn't work like select_related although identical query is executed?

OK. Problem wasn't in my query. It was connected to printing result. Function tried to print user instead of username, so every user had to be fetch from database.
Was

def __unicode__(self):
    return "%s" % self.user

Should be

def __unicode__(self):
    return self.username