Your use case is not very clear. If you are simply "running a few trivial calculations and storing the info" then you could use a function in the database to do this for you - pulling data directly from Table A and storing the result in Table B. Data in Table B could then be later edited using the usual Django functionality.
As a side note: a trip to the database to get data is not "useless" if you need that data for some reason and it is not already present in your app. On Thu, 21 Mar 2019 at 19:06, Dylan Young <dylanyoungmei...@gmail.com> wrote: > For example using made-up syntax: > > Entry.objects.create(start=F(Recurrence.objects.filter(pk=r_id), > 'start_time')) > > Note that we can't use `get` since the whole point is to avoid all the > useless round-trips to the DB. > > Best, > > Casey > > On Thu, 21 Mar 2019 at 13:18, Dylan Young <dylanyoungmei...@gmail.com> > wrote: > >> It's not a recalculation. It's instantiation. >> >> Instance data diverges from the factory data and needs to be >> independently editable. >> >> Best, >> >> Casey >> >> Le jeu. 21 mars 2019 2:52 a.m., Derek <gamesb...@gmail.com> a écrit : >> >>> Permanently storing data that can be recalculated from existing data is >>> a practice specific to the needs of particular applications. >>> >>> Have you perhaps considered making use of the "view" table functionality >>> available in most databases? >>> >>> For example, in PostgreSQL you can create a materialized view which >>> "caches the result of a complex expensive query and then allow you to >>> refresh this result periodically." - see >>> http://www.postgresqltutorial.com/postgresql-materialized-views/ >>> >>> >>> On Tuesday, 19 March 2019 17:34:11 UTC+2, Dylan Young wrote: >>>> >>>> Hey all: >>>> >>>> I often find myself fetching data from models in the database only to >>>> run a few trivial calculations and store the info in a different model. >>>> >>>> Is there an established ORM pattern for directly creating objects in >>>> the DB based on the fields of other models? >>>> >>>> Sorry if this is obvious, but I couldn't find much on this in my web >>>> searching. >>>> >>>> >>>> Best, >>>> >>>> Casey >>>> >>> -- >>> 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 django-users+unsubscr...@googlegroups.com. >>> To post to this group, send email to django-users@googlegroups.com. >>> Visit this group at https://groups.google.com/group/django-users. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/django-users/a1c55adc-c5fa-465c-8740-3a741bc22686%40googlegroups.com >>> <https://groups.google.com/d/msgid/django-users/a1c55adc-c5fa-465c-8740-3a741bc22686%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> For more options, visit https://groups.google.com/d/optout. >>> >> -- > You received this message because you are subscribed to a topic in the > Google Groups "Django users" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/django-users/RDU_KsRqd90/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > django-users+unsubscr...@googlegroups.com. > To post to this group, send email to django-users@googlegroups.com. > Visit this group at https://groups.google.com/group/django-users. > To view this discussion on the web visit > https://groups.google.com/d/msgid/django-users/CAPGJNu40H%3Du5bLLUYYosHpKNDsH7xMFPg-7GU%2B_fHCV59SknyA%40mail.gmail.com > <https://groups.google.com/d/msgid/django-users/CAPGJNu40H%3Du5bLLUYYosHpKNDsH7xMFPg-7GU%2B_fHCV59SknyA%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > 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 django-users+unsubscr...@googlegroups.com. To post to this group, send email to django-users@googlegroups.com. Visit this group at https://groups.google.com/group/django-users. To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/CAF1Wu3NkZCsU8oxLnuGPBtkWpPnq_L_H-o2dVb1rMUjm0pdW3A%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
