I normally use something like this "Tag.object.annotate(num_post=Count('post')).filter(num_post__gt=2)" to get tags with more than 2 posts. I want to get number of posts with a field value (e.g post.published=True) and annote over them so that I get tags with number of published posts bigger than some value. How would I do that?
Edit:
What I want is not filter over annotated objects. What I want is something like this: Tag.objects.annotate(num_post=Count("posts that have published field set to true!")). What I am trying to learn is, how to put post that have published field set to true in Count function.
You can just replace the 2 in ..._gt=2 with some other variable - for example, a variable that gets passed into the view, or a request.GET value, or similar.
Is that what you're trying to do?
Related
Hi I am doing a query like
user_list = Myuser.objects.filter(status=active)
now I want to add a new filed matching_percentage to a user who query it , Like want to show how much it matches to your profile. Now I searched annotate function but till now I found that you cant assign a custom calculated value to new filed .
So Is there any way to assign to a filed int values to show how much it matches my profile on run time by a algorithm ?
Update
I am trying something like this
query=MyUser.objects.annotate(annotated_field=Value(MyFunction(F('id')), output_field=IntegerField()))\
.filter(id__in=ids)
F('id') is not converting to ID just passing in function as a string
I have a model with some HStoreField attributes and I can't seem to use Django's ORM HStoreField to query those values using LIKE.
When doing Model.objects.filter(hstoreattr__values__contains=['text']), the queryset only contains rows in which hstoreattr has any value that matches text exactly.
What I'm looking for is a way to search by, say, te instead of text and those same rows be returned as well. I'm aware this is possible in a raw PostgreSQL query but I'm looking for a solution that uses Django ORM.
If you want to check value of particular key in every object if it contains 'te', you can do:
Model.objects.filter(hstoreattr__your_key__icontains='te')
If you want to check if any key in your hstore field contains 'te', you will need to create your own lookup in django, because by default django won't do such thing. Refer to custom lookups in django docs for more info.
As far as I can remember, you cannot filter in values. If you want to filter in values, you have to pass a column and value you are referencing to. When you want it to be case insensitive use __icontains.
Although you cannot filter by all values, you can filter by all keys. Just like you showed in your code.
If you want to search for 'text' in all objects in key named let's say 'fo' - just do smth like this:
Model.objects.filter(hstoreattr__icontains={'fo': 'text'})
I want to attach a field value (id) to a QS like below, but Django throws a 'str' object has no attribute 'lookup' error.
Book.objects.all().annotate(some_id='somerelation__id')
It seems I can get my id value using Sum()
Book.objects.all().annotate(something=Sum('somerelation__id'))
I'm wondering is there not a way to simply annotate raw field values to a QS? Using sum() in this case doesn't feel right.
There are at least three methods of accessing related objects in a queryset.
using Django's double underscore join syntax:
If you just want to use the field of a related object as a condition in your SQL query you can refer to the field field on the related object related_object with related_object__field. All possible lookup types are listed in the Django documentation under Field lookups.
Book.objects.filter(related_object__field=True)
using annotate with F():
You can populate an annotated field in a queryset by refering to the field with the F() object. F() represents the field of a model or an annotated field.
Book.objects.annotate(added_field=F("related_object__field"))
accessing object attributes:
Once the queryset is evaluated, you can access related objects through attributes on that object.
book = Book.objects.get(pk=1)
author = book.author.name # just one author, or…
authors = book.author_set.values("name") # several authors
This triggers an additional query unless you're making use of select_related().
My advice is to go with solution #2 as you're already halfway down that road and I think it'll give you exactly what you're asking for. The problem you're facing right now is that you did not specify a lookup type but instead you're passing a string (somerelation_id) Django doesn't know what to do with.
Also, the Django documentation on annotate() is pretty straight forward. You should look into that (again).
You have <somerelation>_id "by default". For example comment.user_id. It works because User has many Comments. But if Book has many Authors, what author_id supposed to be in this case?
I have two fields that run throughout a website that I would like to match so that when a user inputs a value either of the fields, it will match the other field. I'm using Sitecore Rocks and am trying to use a query to do this.
select ##h1#, ##Title#
from /sitecore/Content/Home//*[##h1# !="##Title#"];
update set ##h1# = ##Title# from /sitecore/Content/Home//*[##Title# = "<id>"];
What am I missing here?
This article talks about tapping in to the item:saving event which allows you to compare the fields values of the item before and after the changes:
http://www.sitecore.net/Community/Technical-Blogs/John-West-Sitecore-Blog/Posts/2010/11/Intercepting-Item-Updates-with-Sitecore.aspx
Using this, you can determine which field has been amended, then change the other to match.
I've had to do something similar to this when a new field was added, and we wanted to set the initial value equal to an existing field. It may be a bug in Sitecore Rocks, but I found it would only update a field when a static value was part of the query.
When I ran ##h1# = ##Title#, the query analyzer would return the correct number of items updated, but no values were actually updated. However, ##h1# = '<id>' worked perfectly. After trying a number of things, I found this did what I wanted.
update set ##h1# = '' + ##Title# from /sitecore/Content/Home//*[##Title# = "<id>"];
I hope that helps.
I have a model that contains a foreign key value, then in the form generated from this model, I want to auto select the record's key according to the record I'm adding the form's contents to...I've tried the below code, but it tells me QuerySet doesn't contain vehicle
stock = Issues.objects.filter(vehicle=id)
form = IssuesForm(initial={'id_vehicle': stock.vehicle})
I'm a bit new to django btw so any ideas are highly appreciated
filter always gives a QuerySet, which is a set of values. If you just want a single object, you should use get.
However I don't really understand why you need to do the lookup at all. You have the id value already, since you are using it to look up stock. So why don't you just pass id as the value for id_vehicle?