I am trying to do something pretty simple and trivial but with no luck.
I am using django-rating to rate specific objects on my site.
On my model which I wanted to rate I have a field :
rating = RatingField(range=5)
Now , all I want is to filter all of the objects which have a rate of 2 and aobve for example.
If rating was IntegerField for example, I would only need to do :
objects.filter( rating__gte = 2)
how can I do the same using django-rating ?
Reading django-rate documentation I found this trick to sort by rate:
# In this example, ``rating`` is the attribute name for your ``RatingField``
qs = qs.extra(select={
'rating': '((100/%s*rating_score/(rating_votes+%s))+100)/2'
% (MyModel.rating.range, MyModel.rating.weight)
})
qs = qs.order_by('-rating')
Perhaps you can modify this code sample and use extra where to get your results:
qs = qs.extra(where=[
'((100/%s*rating_score/(rating_votes+%s))+100)/2 >= 2 ' %
(MyModel.rating.range, MyModel.rating.weight) ,
])
Related
I'm making a project and want to use limit for fetch data how can i use limit if there are any function or any way i can give limit to my fetching data
i expect the output of (2019, 12, 27)(2019, 6, 30) to be (2019, 12, 27) but it fetching all records
def maintenancefunction(request): #maintenance page function
if 'user' not in request.session:
return redirect('/login')
else:
if request.session.has_key('user'):
abc=request.session['user']
today = date(2019,1,1) # today= date.today.().strftime('%d/%m/%Y')
next_date=today.strftime('%Y-%m-%d')
lastdate= today + timedelta(days=180)
new_date= lastdate.strftime('%Y-%m-%d')
duedate=maintanance_table.objects.values_list('maintanance_todate').filter(user_email=abc).order_by('maintanance_todate').reverse()
# # newduedate=duedate.strftime('%Y-%m-%d')
print("DueDate:",duedate)
checkstatus=maintanance_table.objects.filter(user_email=abc).filter(maintanance_status="PAID").order_by('maintanance_todate').reverse()
if checkstatus:
lastdate = lastdate + timedelta(days=180)
new_date = lastdate.strftime('%Y-%m-%d')
else:
lastdate=lastdate
new_date= lastdate.strftime('%Y-%m-%d')
return render(request,"maintenance.html", {'abc':abc,'new_date':new_date})
else:
return render(request,"login.html")
return render(request,"maintenance.html")
You can add range at the end of the query like [1-10] and if you want the first record then just put [0] at the end of the query. If you want specific record then put its number at the end of the query like [5] or [3] etc.
duedate=maintanance_table.objects.values_list('maintanance_todate').filter(user_email=abc).order_by('maintanance_todate').reverse()[1-10]
checkstatus=maintanance_table.objects.filter(user_email=abc).filter(maintanance_status="PAID").order_by('maintanance_todate').reverse()[1-10]
Is there any way to improve the accuracy of Full Text Search on Postgres? I'm using it with Django and a simple search for invest doesn't return results with the word investor. I assume this is because the stemming algorithm is returning invest* and investor as two different stems.
def get_queryset(self):
query_string = self.request.GET.get('q')
vector = SearchVector('description', weight='A') + SearchVector('location', weight='A') + SearchVector('name', weight='A')
query = SearchQuery(query_string)
return PeopleSnapshot.objects.annotate(rank=SearchRank(vector, query)).order_by('-rank')
For your particular example a "synonym dictionary" should help.
There are also more sophisticated "thesaurus dictionaries" and you can customise the actual stemming by changing the "ispell dictionary". Both mentioned on that same page.
I assume that you are using the english text search configuration.
investor is not reduced to invest by the stemming algorithm:
SELECT to_tsvector('english', 'investor');
to_tsvector
--------------
'investor':1
(1 row)
If you want a prefix match, you'll have to do it like this:
SELECT to_tsvector('english', 'investor')
## to_tsquery('english', 'invest:*');
?column?
----------
t
(1 row)
I am looking for fast method to count model's objects created within past 30 days, for each day separately. For example:
27.07.2013 (today) - 3 objects created
26.07.2013 - 0 objects created
25.07.2013 - 2 objects created
...
27.06.2013 - 1 objects created
I am going to use this data in google charts API. Have you any idea how to get this data efficiently?
items = Foo.objects.filter(createdate__lte=datetime.datetime.today(), createdate__gt=datetime.datetime.today()-datetime.timedelta(days=30)).\
values('createdate').annotate(count=Count('id'))
This will (1) filter results to contain the last 30 days, (2) select just the createdate field and (3) count the id's, grouping by all selected fields (i.e. createdate). This will return a list of dictionaries of the format:
[
{'createdate': <datetime.date object>, 'count': <int>},
{'createdate': <datetime.date object>, 'count': <int>},
...
]
EDIT:
I don't believe there's a way to get all dates, even those with count == 0, with just SQL. You'll have to insert each missing date through python code, e.g.:
import datetime
# needed to use .append() later on
items = list(items)
dates = [x.get('createdate') for x in items]
for d in (datetime.datetime.today() - datetime.timedelta(days=x) for x in range(0,30)):
if d not in dates:
items.append({'createdate': d, 'count': 0})
I think this can be somewhat more optimized solution with #knbk 's solution with python. This has fewer iterations and iterations inside SET is highly optimized in python (both in processing and in CPU-cycles).
from_date = datetime.date.today() - datetime.timedelta(days=7)
orders = Order.objects.filter(created_at=from_date, dealer__executive__branch__user=user)
orders = orders.annotate(count=Count('id')).values('created_at').order_by('created_at')
if len(orders) < 7:
orders_list = list(orders)
dates = set([(datetime.date.today() - datetime.timedelta(days=i)) for i in range(6)])
order_set = set([ord['created_at'] for ord in orders])
for dt in (order_set - dates):
orders_list.append({'created_at': dt, 'count': 0})
orders_list = sorted(orders_list, key=lambda item: item['created_at'])
else:
orders_list = orders
When I use extra in a certain way on a Django queryset (call it qs), the result of qs.count() is different than len(qs.all()). To reproduce:
Make an empty Django project and app, then add a trivial model:
class Baz(models.Model):
pass
Now make a few objects:
>>> Baz(id=1).save()
>>> Baz(id=2).save()
>>> Baz(id=3).save()
>>> Baz(id=4).save()
Using the extra method to select only some of them produces the expected count:
>>> Baz.objects.extra(where=['id > 2']).count()
2
>>> Baz.objects.extra(where=['-id < -2']).count()
2
But add a select clause to the extra and refer to it in the where clause, and the count is suddenly wrong, even though the result of all() is correct:
>>> Baz.objects.extra(select={'negid': '0 - id'}, where=['"negid" < -2']).all()
[<Baz: Baz object>, <Baz: Baz object>] # As expected
>>> Baz.objects.extra(select={'negid': '0 - id'}, where=['"negid" < -2']).count()
0 # Should be 2
I think the problem has to do with django.db.models.sql.query.BaseQuery.get_count(). It checks whether the BaseQuery's select or aggregate_select attributes have been set; if so, it uses a subquery. But django.db.models.sql.query.BaseQuery.add_extra adds only to the BaseQuery's extra attribute, not select or aggregate_select.
How can I fix the problem? I know I could just use len(qs.all()), but it would be nice to be able to pass the extra'ed queryset to other parts of the code, and those parts may call count() without knowing that it's broken.
Redefining get_count() and monkeypatching appears to fix the problem:
def get_count(self):
"""
Performs a COUNT() query using the current filter constraints.
"""
obj = self.clone()
if len(self.select) > 1 or self.aggregate_select or self.extra:
# If a select clause exists, then the query has already started to
# specify the columns that are to be returned.
# In this case, we need to use a subquery to evaluate the count.
from django.db.models.sql.subqueries import AggregateQuery
subquery = obj
subquery.clear_ordering(True)
subquery.clear_limits()
obj = AggregateQuery(obj.model, obj.connection)
obj.add_subquery(subquery)
obj.add_count_column()
number = obj.get_aggregation()[None]
# Apply offset and limit constraints manually, since using LIMIT/OFFSET
# in SQL (in variants that provide them) doesn't change the COUNT
# output.
number = max(0, number - self.low_mark)
if self.high_mark is not None:
number = min(number, self.high_mark - self.low_mark)
return number
django.db.models.sql.query.BaseQuery.get_count = quuux.get_count
Testing:
>>> Baz.objects.extra(select={'negid': '0 - id'}, where=['"negid" < -2']).count()
2
Updated to work with Django 1.2.1:
def basequery_get_count(self, using):
"""
Performs a COUNT() query using the current filter constraints.
"""
obj = self.clone()
if len(self.select) > 1 or self.aggregate_select or self.extra:
# If a select clause exists, then the query has already started to
# specify the columns that are to be returned.
# In this case, we need to use a subquery to evaluate the count.
from django.db.models.sql.subqueries import AggregateQuery
subquery = obj
subquery.clear_ordering(True)
subquery.clear_limits()
obj = AggregateQuery(obj.model)
obj.add_subquery(subquery, using=using)
obj.add_count_column()
number = obj.get_aggregation(using=using)[None]
# Apply offset and limit constraints manually, since using LIMIT/OFFSET
# in SQL (in variants that provide them) doesn't change the COUNT
# output.
number = max(0, number - self.low_mark)
if self.high_mark is not None:
number = min(number, self.high_mark - self.low_mark)
return number
models.sql.query.Query.get_count = basequery_get_count
I'm not sure if this fix will have other unintended consequences, however.
Django documents give this example of associating extra data with a M2M relationship. Although that is straight forward, now that I am trying to make use of the extra data in my views it is feeling very clumsy (which typically means "I'm doing it wrong").
For example, using the models defined in the linked document above I can do the following:
# Some people
ringo = Person.objects.create(name="Ringo Starr")
paul = Person.objects.create(name="Paul McCartney")
me = Person.objects.create(name="Me the rock Star")
# Some bands
beatles = Group.objects.create(name="The Beatles")
my_band = Group.objects.create(name="My Imaginary band")
# The Beatles form
m1 = Membership.objects.create(person=ringo, group=beatles,
date_joined=date(1962, 8, 16),
invite_reason= "Needed a new drummer.")
m2 = Membership.objects.create(person=paul, group=beatles,
date_joined=date(1960, 8, 1),
invite_reason= "Wanted to form a band.")
# My Imaginary band forms
m3 = Membership.objects.create(person=me, group=my_band,
date_joined=date(1980, 10, 5),
invite_reason= "Want to be a star.")
m4 = Membership.objects.create(person=paul, group=my_band,
date_joined=date(1980, 10, 5),
invite_reason= "Wanted to form a better band.")
Now if I want to print a simple table that for each person gives the date that they joined each band, at the moment I am doing this:
bands = Group.objects.all().order_by('name')
for person in Person.objects.all():
print person.name,
for band in bands:
print band.name,
try:
m = person.membership_set.get(group=band.pk)
print m.date_joined,
except:
print 'NA',
print ""
Which feels very ugly, especially the "m = person.membership_set.get(group=band.pk)" bit. Am I going about this whole thing wrong?
Now say I wanted to order the people by the date that they joined a particular band (say the beatles) is there any order_by clause I can put on Person.objects.all() that would let me do that?
Any advice would be greatly appreciated.
You should query the Membership model instead:
members = Membership.objects.select_related('person', 'group').all().order_by('date_joined')
for m in members:
print m.band.name, m.person.name, m.date_joined
Using select_related here we avoid the 1 + n queries problem, as it tells the ORM to do the join and selects everything in one single query.