i have a models
class FriendsWith(models.Model):
username = models.ForeignKey(User,on_delete=models.CASCADE)
fusername =models.ForeignKey(User,on_delete=models.CASCADE,related_name='fusername')
time = models.DateTimeField(auto_now_add=True)
confirm_request = models.SmallIntegerField(default=1)
blocked_status = models.IntegerField(default=0)
i wanted to search all the friends of currently logged in user.So,i am doing like this
obj1=FriendsWith.objects.filter(username=request.user).select_related('fusername')
obj2=FriendsWith.objects.filter(fusername=request.user).values('username')
obj=obj1 | obj2
friendslist=User.objects.filter(username__in=obj)
Where User is a django User model
I am trying to combine two queryset(obj1 and obj2) set here But it's not working.I can do the same thing in sql by using alias .But here i am not sure what to do.
I am getting this error while performing the above code:
TypeError: Merging 'QuerySet' classes must involve the same values in each case
Please help in achieving this task
I think you should do the 'or' in the filter function:
from django.db.models import Q
friendship = FriendsWith.objects.filter(Q(username=request.user)|Q(fusername=request.user))
friendship is a queryset where the current user can be a username or a fusername. You can use that set to get the alternative user that should be their friend.
Another solution is to use django-friendship. It is a good django library for handling friendship and friend requests between users and so on.
Related
I have made a field facility_id in Django models that should concatenate a specific string "ACCTS-" on the left with each record's id on the right,
My model class is below:
class Facility(models.Model):
...
id = models.BigAutoField(primary_key=True)
facility_id = models.CharField(max_length=50, default=print(f'{"ACCTS-"}{id}'), editable=False)
...
I want to the facility_id field to be storing special and readable human friendly facility_id's of the form: ACCTS-1, ACCTS-2, ACCTS-3, ... corresponding to each individual id.
The migrations didn't throw any errors, however When I try to create the records for this table in the Django Admin, am getting an IntegrityError of:
IntegrityError at /admin/ACCTS_CLYCAS/facility/add/
NOT NULL constraint failed: ACCTS_CLYCAS_facility.facility_id
How do I fix this problem, or what could be the easiest way to implement my problem.
The migrations didn't throw any errors, however When I try to create the records for this table in the Django Admin
That makes sense, since you have set the default=None. Indeed, print(…) returns None and only prints the value to the standard output channel (stdout). It will thus not prepend the value of the id with ACCTS.
If the facility_ids are all just the id prefixed with ACCTS-, you can work with a #property instead:
class Facility(models.Model):
id = models.BigAutoField(primary_key=True)
#property
def facility_id(self):
return f'ACCTS-{self.id}'
You can also try using a post save signal.
Add blank = True to facility_id and then use a post save signal to update the value of facility_id.
You can watch this tutorial on how to use Django Signals
Which query will be more efficient:
for id in user.posts:
Post.objects.get(id=id)
or
posts = Post.objects(user=user_id)
with the next schema
Post(Document):
user = ObjectIdField()
User(Document):
posts = ListField(ObjectIdField())
if there is indexing for user field in the Post document, and an average of 20 posts for each User. Also curious about other usage pattern scenarios
The following block, fires as many database queries as you have post in user.posts so it will be slow anyway.
for id in user.posts:
Post.objects.get(id=id)
but if you use it like this:
Post.objects.get(id__in=user.posts)
Then the performance will be similar to using Post.objects(user=user_id) because the primary key gets indexed by default
I believe you should also use ReferenceField i.o plain ObjectId. They allow for lazy loading of references
class Post(Document):
user = ReferenceField("User")
class User(Document):
name = StringField()
#property
def posts(self):
return Post.objects(user=self)
john = User(name='John').save()
post = Post(user=john).save()
print(john.posts()) # [<Post: Post object>]
I am working on multiple join with Django.
questions = Question.objects.select_related(
'publishedquestionmapping__library_question'
).prefetch_related(
'publishedquestionmapping__library_question__contributor_set__user',
).filter(
hide=False).order_by('-pub_date')[:count]
for question in questions:
contributers = question.publishedquestionmapping.library_question.contributor_set.all()
for contributer in contributers:
print contributer.user
The Error is RelatedObjectDoesNotExist: Contributor has no user.
The problem is that I can use prefetch_related
...contributor_set__user, but I can't use contributer.user?
btw, print contributer.user_id is ok.
This Model Contributer
class Contributor(models.Model):
user = models.ForeignKey(User)
question = models.ForeignKey(Question)
I want to do like contributer.user.username. How should I do that?!
Thanks!
I've got the following models...
class User(ndb.Model):
email = ndb.StringProperty()
username = ndb.StringProperty(indexed=True)
password = ndb.StringProperty()
class Rel(ndb.Model):
user = ndb.KeyProperty(kind=User, indexed=True)
follows = ndb.KeyProperty(kind=User, indexed=True)
blocks = ndb.KeyProperty(kind=User)
I'm trying to make it so a user can follow or block any other number of users.
Using the above setup I'm finding it hard to perform tasks that would been easy with a traditional DBMS.
As a simple example, how would I find all of a given user's followers AND order by username-- keeping in mind when I perform a query on Rel, I'm getting back keys and not user objects?
Am I going about this the wrong way?
You have to do a fetch but you can go about designing it in a better way,
the follows and blocks fields can be lists instead of just key -
follows = ndb.KeyProperty(kind=User, repeated=True)
blocks = ndb.KeyProperty(kind=User, repeated=True)
after this when you need the follows of this user you can get the keys and do an ndb.get_multi(Keys_list) to get all the follows/blocks entities whatever you need.
OR
A better way of doing this -
If you care about the order and want to paginate, you will have to store all the follow/block entities separately,
for example if this is about a user 'a'
Follows entity will have records for each person 'a' follows
class FollowEntity(ndb.Model):
user = ndb.KeyProperty(kind=User)
follow = ndb.KeyProperty(kind=User)
follow_username = ndb.StringProperty()
a query can be
assuming user is an entry from your 'User' Entity.
query = FollowEntity.query(FollowEntity.user == user.key).order(FollowEntity.follow_username)
you can run this query and get the sorted username results, would work well if you use fetch_page to display the results in a batch.
Do the same for BlockEntity too
I need to pass the current user's entire activity log to an html page, but it seems I cannot find any helpful solution regarding the same.
Is it possible? If yes, please direct me in the right way?
Thanks in advance!
Update:
I found a solution making use of a get() call to django's LogEntry model, but I am clueless as to what shall be the appropriate parameters for doing the same.
Yet another UPDATE:
I am looking for a way to access the activity log of a particular user from the django's log entries WITHOUT saving it to any database
Take a look below listed.....Hope it will help::
lets example::
Create Two Field in Models:
last_activity_ip = models.IPAddressField()
last_activity_date = models.DateTimeField(default = datetime(1960, 1, 1))
user = models.OneToOneField(User, primary_key=True)
Since the User and UserActivity models are now related one-to-one we can now type:
Run the Query Like this:
a = User.objects.get(username__exact='mpcabd')
print a.useractivity.last_activity_ip
b = UserActivity.objects.get(user=a)
print b.user.username
** To track the activity use this **
activity = None
try:
activity = request.user.useractivity
except:
activity = UserActivity()
activity.user = request.user
activity.last_activity_date = datetime.now()
activity.last_activity_ip = request.META['REMOTE_ADDR']
activity.save()
return
activity.last_activity_date = datetime.now()
activity.last_activity_ip = request.META['REMOTE_ADDR']
activity.save()
This question don't has a short answer, you can use sentry project by side of main django project. below link can helping you:
https://sentry.readthedocs.org/en/latest/