Thanks for the answer, I just wondered if there was a built-in solution in Django.
On 27/09/14 06:01, tkdchen wrote: > > > On Saturday, September 27, 2014 9:06:58 PM UTC+8, aRkadeFR wrote: > > > > @James Brewer: > > If I change my code, I can have this user_ids list. > > btw, it's filter and not get if you're searching multiple objects (the > > user_ids). > > > > @Alejandro Varas G.: > > That doesn't change the fact that 'User.objects.get(id=X)' will hit the > > database everytime. > > > > Right now, the problem is solved, by creating the AllUserSet, but I think > > my > > code is pretty ugly, and it seems strange to me that the ORM can't handle > > that > > built-in, by caching the .all() or .filter(id__in=users_ids) > > > > > Django actually caches all objects fetched when it evaluates .all or > .filter method. The problem you are facing is that how to reuse the cached > objects efficiently to avoid hitting database with unnecessary SQL queries. > James gave you a good solution. Based on his solution, you don't need to > call the `get' method each time getting user by id. Just iterate users > object and find the right one by comparing id. > > > > > > The ideally solution would be something like: > > > > AllUser = User.objects.all() > > > > for i in user_id: > > AllUser.get(id=i) > > > > > This piece of code would be changed to > > AllUser = User.objects.all() > for i in user_id: > for user in AllUser: > if user.pk == i: > print 'find the user' > > or, even you may construct AllUser to dict to simplify the search > > AllUser = dict((user.pk, user) for user in User.objects.all()) # Here, hit > db, only once > for i in user_id: > user = AllUser.get(i, None) # search by id in memory > if user is not None: > print 'find the user' > > Hope, this could help you. > > But this code hits the database every time the 'get' is called. > > > > > > On 26/09/14 12:36, James Brewer wrote: > > > Do you have a single list of the IDs you want? If so, you can do > > something > > > like `User.objects.get(id__in=user_ids)`. This will fetch all Users > > whose > > > `id` is in some list `user_ids`. > > > > > > Does that help? > > > > > > Happy hacking! > > > > > > James > > > > > > On Fri, Sep 26, 2014 at 11:43 AM, Alejandro Varas G. <[email protected] > > <javascript:>> > > > wrote: > > > > > > > Hi, > > > > > > > > You should use User.objects.get(id=X) > > > > > > > > Best > > > > El 26/09/2014 15:28, "aRkadeFR" <[email protected] <javascript:>> > > escribió: > > > > > > > > > > > > > > Hey! > > > > > > > > > > I'm having a hard time trying to reduce the number of SQL queries on > > a > > > > view. > > > > > > > > > > Basically, I'm fetching all my User, with User.objects.all(), and > > save > > > > this > > > > > queryset as AllUser. > > > > > > > > > > Then every time I need to get the user with the id = X , I'm calling > > a > > > > function > > > > > 'get_user_from_id', that iterate over the AllUser queryset variable, > > and > > > > when > > > > > it finds the id, returns it. > > > > > > > > > > I considerably reduced the number of SQL queries, but I would like > > to > > > > know if > > > > > you think of a better way? > > > > > > > > > > Thank you > > > > > > > > > > -- > > > > > You received this message because you are subscribed to the Google > > > > Groups "Django users" group. > > > > > To unsubscribe from this group and stop receiving emails from it, > > send > > > > an email to [email protected] <javascript:>. > > > > > To post to this group, send email to [email protected] > > <javascript:>. > > > > > Visit this group at http://groups.google.com/group/django-users. > > > > > To view this discussion on the web visit > > > > > > https://groups.google.com/d/msgid/django-users/20140926182939.GA26744%40rkade-thinkpad > > > > > > . > > > > > For more options, visit https://groups.google.com/d/optout. > > > > > > > > -- > > > > You received this message because you are subscribed to the Google > > Groups > > > > "Django users" group. > > > > To unsubscribe from this group and stop receiving emails from it, send > > an > > > > email to [email protected] <javascript:>. > > > > To post to this group, send email to [email protected] > > <javascript:>. > > > > Visit this group at http://groups.google.com/group/django-users. > > > > To view this discussion on the web visit > > > > > > https://groups.google.com/d/msgid/django-users/CAL60nj%2BBtqs9CXu8drOiWPoJ7aUkAKjLqXKCxmR_TMTeOOH%3DGw%40mail.gmail.com > > > > > > < > > https://groups.google.com/d/msgid/django-users/CAL60nj%2BBtqs9CXu8drOiWPoJ7aUkAKjLqXKCxmR_TMTeOOH%3DGw%40mail.gmail.com?utm_medium=email&utm_source=footer> > > > > > > > > . > > > > > > > > For more options, visit https://groups.google.com/d/optout. > > > > > > > > > > > > > > > > -- > > > James Brewer > > > jamesbrewer.io > > > > > > -- > > > You received this message because you are subscribed to the Google > > Groups "Django users" group. > > > To unsubscribe from this group and stop receiving emails from it, send > > an email to [email protected] <javascript:>. > > > To post to this group, send email to [email protected] > > <javascript:>. > > > Visit this group at http://groups.google.com/group/django-users. > > > To view this discussion on the web visit > > https://groups.google.com/d/msgid/django-users/CAKj8pVpqBgpFDQ0BruHXLWe2q1CRURMEejokhMKpD5bfs9hGGA%40mail.gmail.com. > > > > > > > For more options, visit https://groups.google.com/d/optout. > > > > -- > You received this message because you are subscribed to the Google Groups > "Django users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/django-users. > To view this discussion on the web visit > https://groups.google.com/d/msgid/django-users/2d9a29de-9326-4ddc-a716-df9383b2aa32%40googlegroups.com. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "Django users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/django-users. To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/20140928205119.GA22961%40rkade-thinkpad. For more options, visit https://groups.google.com/d/optout.
