Thanks in advance for looking at my django model. I have recently added the "get_absolute_url" method to an existing model, but everytime I try to access it, I get an AttributeError. I defined the "unicode" method when I first created the model and I can call that one without issue. I have not been able to determine what the problem is. Here is my model:
class Project(models.Model):
project_number = models.CharField(max_length=50)
project_lead = models.CharField(max_length=50,blank=True)
project_type = models.CharField(max_length=10,blank=True)
def __unicode__(self):
return self.project_number
def get_absolute_url(self):
return "/project/%i/" % self.id
I invoke the interpreter:
>>>project = Project.objects.get(id=45)
>>>project.__unicode__()
u'987990-A'
>>>project.get_absolute_url()
Traceback (most recent call last):
File "<console>", line 1, in <module>
AttributeError: 'Project' object has no attribute 'get_absolute_url'
Can someone please offer some advice on how to resolve this issue? Thanks so much!
Related
Using autocomplete_fields/search_fields in Django's admin works well to cause a Select2 widget to be used for a ForeignKey field, but I'm getting an error when I set things up to have Select2 widgets rendered on a declared through model in a ManyToManyField relationship. My models are different than the following, but using the example from the Django docs where through models in the admin are discussed as a starting point, I have things set up something like this (the example in the docs has an implicit through model, but I have an explicitly declared through model):
class Person(models.Model):
first_name = models.CharField(max_length=128)
last_name = models.CharField(max_length=128)
class Group(models.Model):
name = models.CharField(max_length=128)
members = models.ManyToManyField(Person, through='Membership', related_name='groups')
class Membership(models.Model):
person = models.ForeignKey('Person', ...)
group = models.ForeignKey('Group', ...)
and in admin.py:
class PersonAdmin(admin.ModelAdmin):
inlines = [MembershipInline,]
search_fields = ('first_name','last_name,)
class MembershipInline(admin.TabularInline):
model = Membership
autocomplete_fields = ('person',)
class GroupAdmin(admin.ModelAdmin):
inlines = [MembershipInline,]
When I go to the GroupAdmin and try to create a membership, the Select2 widget is rendered, but when I try to look up a person, I get this error:
Forbidden (Permission denied): /admin/autocomplete/
Traceback (most recent call last):
File "/virtualenvs/my_virtualenv/lib/python3.8/site-packages/django/utils/datastructures.py", line 84, in __getitem__
list_ = super().__getitem__(key)
KeyError: 'app_label'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/virtualenvs/my_virtualenv/lib/python3.8/site-packages/django/contrib/admin/views/autocomplete.py", line 79, in process_request
app_label = request.GET["app_label"]
File "/virtualenvs/my_virtualenv/lib/python3.8/site-packages/django/utils/datastructures.py", line 86, in __getitem__
raise MultiValueDictKeyError(key)
django.utils.datastructures.MultiValueDictKeyError: 'app_label'
I am using django-jazzmin, so the problem COULD be caused by it, but the Select2 widgets work fine in ForeignKey relationships that are not part of a through model. Someone encountered something similar in Grappelli a year ago, but I can't tell whether this problem is similar.
Any help is very much appreciated.
Not sure if the title is the correct one, sorry for the inconvenience.
I'm having a problem on sending a ManyToManyField from a model to a dictionary using the model_to_dict() Below is my code
models.py
from django.db import models
from django.forms import model_to_dict
from app_1.models import *
class Stuff(models.Model):
thing_1 = models.CharField(max_length=100, null=True, blank=True)
thing_2 = models.ManyToManyField(OtherStuff, blank=True, related_name="thing")
def toJSON(self):
item = model_to_dict(self)
item['thing'] = self.thing.toJSON()
return item
When I run a query and load my Stuff model, I get the following error:
from app_2.models import *
s = Stuff.objects.get(pk=1)
# here is where I send my model to a dictionary
s.toJSON()
Traceback (most recent call last):
File "<input>", line 1, in <module>
File "P:\test\app\app_2\stuff\models.py", line 10, in toJSON
return item
AttributeError: 'ManyRelatedManager' object has no attribute 'toJSON'
I've come across multiple ways of sending a ManyToManyField to a dictionary, however, none of them use the model_to_dict(). I'd like to use this method due to it's simplicity of usage.
With this approach, you'll need to use this syntax:
item['thing'] = [t.toJSON() for t in self.thing_2.all()]
And also, implement the toJSON method for the OtherStuff model.
Or you can use model_to_dict for OtherStuff as well:
def toJSON(self):
item = model_to_dict(self)
item['thing'] = [model_to_dict(t) for t in self.thing_2.all()]
return item
Let's say I have AssetUser model looks like follow.
class AssetUser(models.Model):
user = models.ForeignKey(User, on_delete=models.CASCADE)
my query set looks like follow.
qs = User.objects.get(pk=1)
when i run qs.assetuser_set i am getting error like follow.
Traceback (most recent call last):
File "", line 1, in
AttributeError: 'User' object has no attribute 'assetuser_set'
what mistake i made here.
Django models should be inherited from Model class, so you need to change your code to this:
class AssetUser(models.Model):
user = models.ForeignKey(User, on_delete=models.CASCADE)
I am just exploring how to get around with Django, and i created two models in my Django app.
from django.db import models
#first model
class Person(models.Model):
name = models.CharField(max_length=40)
email = models.CharField(max_length=100)
title = models.CharField(max_length=100)
image = models.CharField(max_length=200)
def __str__(self):
return self.name
#second model
class Skill(models.Model):
person = models.ForeignKey(Person)
skill = models.CharField(max_length=60)
years = models.CharField(max_length=40)
def __str__(self):
return self.skill, self.person
The first model is Person and the second model is Skill. Now how the relation goes is that each Person will have many skills.
Now I can update the database with the data, the admin section of the site also works fine.
On the Django Shell, I try to run the command:
Skill.object.all()
and what i get is the following error:
Traceback (most recent call last):
File "<console>", line 1, in <module>
File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\db\models\query.py", line 235, in __repr__
return '<QuerySet %r>' % data
File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\db\models\base.py", line 572, in __repr__
u = six.text_type(self)
TypeError: __str__ returned non-string (type tuple)
or if i try the command:
Skill.objects.get(pk=1)
i get:
Traceback (most recent call last):
File "<console>", line 1, in <module>
File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\db\models\base.py", line 572, in __repr__
u = six.text_type(self)
TypeError: __str__ returned non-string (type tuple)
However if i run a command such as :
Skill.objects.get(skill='Photoshop').person.name
I get the name of the person who has the skill "Photoshop."
I am trying to understand what I am doing wrong here; maybe I am not supposed to query a table with the foreign key this way? Or maybe I am doing something wrong.
Well, finally what I like to query is, I want to find all the skills of a Person with a given name or primary key.
__str__ should return a str. So Change something like this
return self.skill, self.person
to
return "%s-%s" %(self.skill, self.person.name)
Your __str__ method returns a tuple (self.skill, self.person), it must return those object's str representation. In order to achieve that, change:
return self.skill, self.person
to
return "{}, {}".format(self.skill, self.person)
I'm trying to work with Django model created from a mysql database which has composite foreign keys.
My models.py goes like this.
class Make(models.Model):
idmake = models.IntegerField(primary_key=True)
make = models.CharField(max_length=20L, unique=True, blank=True)
def __unicode__(self):
return self.make
class Meta:
db_table = 'make'
class Models(models.Model):
idmodels = models.IntegerField(primary_key=True, unique=True)
make = models.ForeignKey(Make, db_column='make', to_field='make')
model = models.CharField(max_length=45L, unique=True)
resource_type = models.CharField(max_length=7L)
def __unicode__(self):
return self.model
class Meta:
db_table = 'models'
class Systems(models.Model):
idsystems = models.IntegerField(primary_key=True, unique=True)
make = models.ForeignKey(Models, null=True, db_column='make', blank=True, related_name='system_make')
model = models.ForeignKey(Models, null=True, db_column='model', to_field = 'model', blank=True, related_name='system_model')
serial_num = models.CharField(max_length=45L, blank=True)
service_tag = models.CharField(max_length=45L, blank=True)
mac = models.CharField(max_length=45L, unique=True)
Now when I try to access the make field of Systems I get a ValueError.
>>> s = Systems.objects.get(pk=1)
>>> s.model
<Models: model11>
>>> s.model.make
<Make: make1>
>>> s.make
Traceback (most recent call last):
File "<console>", line 1, in <module>
File "/usr/lib/python2.7/site-packages/django/db/models/fields/related.py", line 384, in __get__
rel_obj = qs.get(**params)
File "/usr/lib/python2.7/site-packages/django/db/models/query.py", line 395, in get
clone = self.filter(*args, **kwargs)
File "/usr/lib/python2.7/site-packages/django/db/models/query.py", line 669, in filter
return self._filter_or_exclude(False, *args, **kwargs)
File "/usr/lib/python2.7/site-packages/django/db/models/query.py", line 687, in _filter_or_exclude
clone.query.add_q(Q(*args, **kwargs))
File "/usr/lib/python2.7/site-packages/django/db/models/sql/query.py", line 1271, in add_q
can_reuse=used_aliases, force_having=force_having)
File "/usr/lib/python2.7/site-packages/django/db/models/sql/query.py", line 1202, in add_filter
connector)
File "/usr/lib/python2.7/site-packages/django/db/models/sql/where.py", line 71, in add
value = obj.prepare(lookup_type, value)
File "/usr/lib/python2.7/site-packages/django/db/models/sql/where.py", line 339, in prepare
return self.field.get_prep_lookup(lookup_type, value)
File "/usr/lib/python2.7/site-packages/django/db/models/fields/__init__.py", line 1003, in get_prep_lookup
return super(IntegerField, self).get_prep_lookup(lookup_type, value)
File "/usr/lib/python2.7/site-packages/django/db/models/fields/__init__.py", line 322, in get_prep_lookup
return self.get_prep_value(value)
File "/usr/lib/python2.7/site-packages/django/db/models/fields/__init__.py", line 997, in get_prep_value
return int(value)
ValueError: invalid literal for int() with base 10: 'make1'
I'm not allowed to change the tables and relations in the database. I'm very new to Django and I'm unable to figure out what is the correct fix for this issue. Basically I would like to be able to get and set the make field of the Systems model directly. Can someone guide me on how I should go about doing this? My initial thoughts were that I would have to create a custom ForeignKey field.
I suspect your codes don't match your DB schema. In this line:
make = models.ForeignKey(Models, null=True, db_column='make', blank=True, related_name='system_make')
Models is supposed to be Make, isn't it? And your Systems.model has to_field = 'model', did you miss to_field='make' for Systems.make? I suggest you to drop the whole DB, run syncdb and create test data again. Then see if the error still happen.
Some more tips for your code:
as your defined to_field = 'model' and to_field='make', you'd better to consider add db_index=True for make and model fields. Otherwise query performance may be bad when your dataset is large
if you're going to set Make.make and Models.model to be unique and indexed, they seems to be qualified as primary key. Are the idmake and idmodels really necessary in your case?
primary_key=True guarantees unique. unique=True is redundant
Django conversions use singular form for model definition. I.e., use Model System, rather than Models Systems. Also, usually we use id, rather than idmake, idmodels. Those are just conversions, up to you
I discovered the answer, rather by accident. Would like to share for anyone facing similar problem.
To access make directly from Systems
>>> s = Systems.objects.get(pk=1)
>>> s.model
<Models: model11>
>>> s.model.make
<Make: make1>
>>> s.make_id
u'make1'
To set make directly from a Systems object
>>> s.make_id = Models.objects.get(model='model21').make.make
>>> s.save()
>>> s.make_id
u'make2'
Be warned. This will not work if the get method of Models returns multiple or no model objects. For example if my Models table was as:
then
>>>> Models.objects.get(model='unknown').make.make
Traceback (most recent call last):
....
MultipleObjectsReturned: get() returned more than one Models -- it returned 2!
>>> Models.objects.get(model='not known').make.make
Traceback (most recent call last):
....
DoesNotExist: Models matching query does not exist.
I fell the programmer needs to be cautious about these things.
EDIT
From comments by #ZZY to this answer and to his own answer
class Models(models.Model):
idmodels = models.IntegerField(primary_key=True, unique=True)
make = models.ForeignKey(Make, db_column='make', to_field='make')
model = models.CharField(max_length=45L, unique=True)
resource_type = models.CharField(max_length=7L)
def __unicode__(self):
return self.model
class Meta:
db_table = 'models'
unique_together = ("make", "model")
And also since model field in Models is unique, the scenario described by me should not occur in a correct table