Hi, I am not cleat of what you suggested as a dictionary method and how you are going to use it.
But any way let me check my guesses and I will be back. On Mon, Aug 1, 2016 at 11:25 PM, Yoann Duriaud <[email protected]> wrote: > Thanks for the tip, but besides defining the type of the output it is > unclear how this can be used to perform a date difference operation. > > What I would need is to convert *timezone.now()* into a date constant > that can be understood by the database, whatever the database is. If I > leave it as it is, I get the str() conversion, which is meaningless for the > database. Even if I find some format *dd-mm-yyyy* that works with a given > database, I wouldn't be sure that it works with other databases. I need the > ORM to perform the conversion *Date Object -> Database date constant*. > > Then comes the date difference operation. Same thing: either the database > understands the minus sign with date format, or it doesn't and need some > DATEDIFF operator. Again I would need the ORM to explicitly set the right > operator. > My guess at the moment is that this cannot be achieved with Django ORM. I > may apply the dict method and work with the dictionary instead, so that I > can add custom fields more easily. > > Yoann > > > > Le dimanche 31 juillet 2016 09:25:58 UTC+2, Constantine Covtushenko a > écrit : >> >> Hi Yoann, >> >> I am not sure exactly but believes you are on the right way. >> Try improve your expression with ExpressionWrapper, as said here >> <https://docs.djangoproject.com/en/1.9/ref/models/expressions/#using-f-with-annotations> >> . >> Probably the problem is that you use values of different types in your >> expression. >> >> Regards >> >> On Sat, Jul 30, 2016 at 11:35 PM, Yoann Duriaud <[email protected]> >> wrote: >> >>> Hello, >>> I would like to annotate a query with the following expression: ([Due >>> Date] - [Now])/[Interval]. [Due Date] and [Interval] are fields from the >>> database, while [Now] should be "equal" to timezone.now(). >>> >>> So this would look like: >>> .annotate(ratio=(F('due_date')-timezone.now())/F('Interval')) >>> >>> but this does not work. Does someone know how the expression should be >>> written (if it is indeed feasible with Django ORM)? >>> >>> Thanks for your help! >>> >>> Yoann >>> >>> -- >>> 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 https://groups.google.com/group/django-users. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/django-users/03dedd39-142f-468a-b6fd-b7ec551862e8%40googlegroups.com >>> <https://groups.google.com/d/msgid/django-users/03dedd39-142f-468a-b6fd-b7ec551862e8%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 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 https://groups.google.com/group/django-users. > To view this discussion on the web visit > https://groups.google.com/d/msgid/django-users/60119a06-5b1f-4e23-a142-627c65f14017%40googlegroups.com > <https://groups.google.com/d/msgid/django-users/60119a06-5b1f-4e23-a142-627c65f14017%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 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 https://groups.google.com/group/django-users. To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/CAK52boXEZ%2BygOsiaE%3DZf5TbDMLLyixR--keV6jXXCKJPC_3w4Q%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
