Thanks a lot Malcolm for your explanatory information. I think I get the concept now :)
On Dec 20, 9:36 pm, Malcolm Tredinnick <malc...@pointy-stick.com> wrote: > On Fri, 2008-12-19 at 11:10 -0800, Fereshteh wrote: > > Hi, > > I am trying to add a filtering functionality to my web application. I > > create a WHERE clouse text in the client side as text and post it to > > the server. > > > My Django modele lookes like this: > > class Projects(models.Model): > > id = models.AutoField(primary_key=True) > > name = models.TextField() > > class Meta: > > db_table = 'projects' > > > class Timesheet(models.Model): > > ts_id = models.AutoField(primary_key=True) > > user = models.ForeignKey(Users, db_column='ts_user', > > related_name='ts_user_child') > > project = models.ForeignKey(Projects, db_column='project', > > related_name='project_child', null='true') > > class Meta: > > db_table = 'timesheet' > > > I use the following in my Django view to retrieve the data according > > to the filtering argument received: > > filter_str = request.POST['filter_str'] > > #filter_str contains something like this: "project__name = 'Django > > supported web app'" > > Timesheet.objects.filter(user = id).extra(where = [filter_str]) > > > But it gives me the error: > > > column "project__name" does not exist > > > Without using extra the same query works fine so the column does > > exist. > > Your conclusion here is incorrect. There is no column in the database > table called "project__name". When you pass that string to a filter() > call, Django does a lot of processing and works out the right database > table and column name to use for the query. Have a look at the output of > > Timesheet.objects.filter(project__name="foo").query.as_sql() > > for example. You will not see any reference to a column called > "project__name" there. If you are using extra(), you need to use the > correct column names: extra() only exists as a way to write almost raw > SQL portions. > > It sounds a lot like you really want to be using a second filter() call, > not an extra() call. > > Regards, > Malcolm --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@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 -~----------~----~----~----~------~----~------~--~---
