Hi Tobias. I've done a bit of stuff on this, and found there were actually limited changes that need to be made to django to got this to work.
https://schinckel.net/2020/09/15/django-properties-from-expressions%2C-or-computedfield-part-2/ I haven't touched it much since then (although I'm keen to revisit it, actually), but it's actually possible that we can do it without any changes to Django. https://github.com/schinckel/django-shared-property Matt. On Sunday, March 14, 2021 at 11:46:15 PM UTC+10:30 Tobias Bengfort wrote: > Hi, > > a while back there has been a discussion about calculated model fields: > > https://groups.google.com/g/django-developers/c/ADSuUUuZp3Q/m/5o02Lp_jCwAJ > > The main benefit would be that these would be available in cases where > annotations are currently not available, e.g. related queries or admin > lists (see #14336). > > Note that the topic of fields that have both a DB and python > implementation was discussed and the consensus was that the python > equivalents could be added by a separate library, if required. So I am > only talking about the database part here. > > The linked discussion was mainly about *what* is desired, not *how* it > could be done. I also noticed that the fellows did not participate in > that discussion. > > I would like to have a shot at this topic. So I am interested in: > > - Do you think this is even possible/worth the effort? > - How could this be implemented and what would be potential challenges? > - Is it possible to implement this in a third party library or does it > require changes to django itself? > > I would probably start with a non-editable, non-concrete model field > (similar to GenericForeignKey or ForeignObjRel). But I have no clue yet > how to integrate that with QuerySet/Query. > > thanks > tobias > -- You received this message because you are subscribed to the Google Groups "Django developers (Contributions to Django itself)" group. To unsubscribe from this group and stop receiving emails from it, send an email to django-developers+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/django-developers/8d325f4e-9c20-4268-9c46-6f682911ac5dn%40googlegroups.com.
