There is also an online version of one of the django books here:
http://djangobook.com/
On Jan 17, 5:08 pm, pfwd <pfwdt...@googlemail.com> wrote:
> Thanks fantastic thank you
> I was also able to do:
> result = obj.task_set.aggregate(Count('id'))['id__count']
> to get the a count of the tasks for quote
>
> I don't suppose you know any good books regarding Python/Django that I
> could buy to help me learn the syntax better?
>
> Many thanks
>
> On Jan 17, 10:15 pm, Daniel Roseman <dan...@roseman.org.uk> wrote:
>
>
>
> > On Jan 17, 8:28 pm, pfwd <pfwdt...@googlemail.com> wrote:
>
> > > Hi am very new to Django/Python and I need some help with a model
> > > method
>
> > > I have two tables Linked by a foreign key and their forms are embedded
> > > in the admin interface.
> > > One table is called Quote and one table is called Task. The task table
> > > has a field called time_taken
> > > In the Quote list I want to display the total amount of time to under
> > > go all the tasks in each quote.
>
> > > This is what I'm doing and its just displaying (None) in the list
>
> > > class QuoteAdmin(admin.ModelAdmin):
> > > fieldset = [
> > > (None, {'fields': ['q_number']})
> > > ]
> > > inlines = [TaskInline]
>
> > > list_display = ('q_number', 'total_time','created_date')
>
> > > def total_time(self,queryset):
> > > task_objs = self.Task.objects.all()
>
> > > total_time = 'No time taken'
>
> > > for record in task_objs:
> > > total_time = total_time + record.time_taken
> > > return total_time
>
> > > I'm trying to get all the tasks for each quote by doing
> > > self.Task.objects.all() and then looping through them and adding the
> > > time_taken to the var total_time.
>
> > > I guess this syntax is just plain wrong or the method is not being
> > > called as its not showing any errors
> > > I have a javascript/PHP background and I would like to learn more
> > > Python
> > > - Please be kind :)
>
> > OK a few pointers.
>
> > * a custom list_display method takes parameters (self, obj), where obj
> > is the object being displayed in that row - here it's an instance of
> > Quote.
> > * 'self.Task' means nothing. You want to get the tasks related to the
> > Quote, which is in 'obj', so you use 'obj.task_set.all()'. With this,
> > your code would work as is.
> > * A nicer way of doing it would be to get the DB to sum the time_taken
> > values. This should work:
> > from django.db.models import Sum
> > return obj.task_set.aggregate(Sum('time_taken'))
> > ['time_taken__sum']
> > (the square brackets at the end are needed because 'aggregate' returns
> > a dictionary, and we just want the value from there).
> > --
> > DR.
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