ok, thank for reply. I think that with this query:
" AA.object.filter(...).select_related( field related in BB ) " The impact in the performance is minimun But with this query " AA.object.filter(...).select_related() " the impact is higher, because the first query do an unique "join", but the second "join" can do multiple "join"s and I just need the AA fields and the BB fields. Is this idea correct? On 15 oct, 12:27, Daniel Roseman <dan...@roseman.org.uk> wrote: > On Oct 15, 4:19 pm, refreegrata <refreegr...@yahoo.com> wrote: > > > > > Hello, how can i get fields from different tables related for a > > foreign key? > > > When I do a inner join like > > > AA.objects.filter(bb__field = ...) ... > > > I just can access to the AA fields, and not to fields in the other > > table > > > in a normal query i can do something like "select AA.*, BB.* FROM. AA > > inner join BB..." > > but in django the resultant query is "select AA.* FROM. AA inner join > > BB..." > > > Now i use select_related for solve this problem isn't recommended , > > because this query has an impact in the server performance. How i can > > solve this? > > > Thanks for read, and sorry for my poor english. > > select_related *is* the answer to this question. Of cours all joins > have an impact on server performance, because you're asking the > database to do more work, but this is likely to be very very small, > and there isn't a way of doing what you want without some form of > join. > -- > DR. -- You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-us...@googlegroups.com. To unsubscribe from this group, send email to django-users+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/django-users?hl=en.
