Questions tagged [django-constraints]
27 questions
8
votes
1 answer
Using Django's CheckConstraint with annotations
I have a Django model where each instance requires a unique identifier that is derived from three fields:
class Example(Model):
type = CharField(blank=False, null=False) # either 'A' or 'B'
timestamp =…
Matthew Trevor
- 14,354
- 6
- 37
- 50
3
votes
0 answers
What is best practice when using ValidationError and Constraint (new in Django 2.2)?
Edit: I am using PostgreSQL
I have a model that has 4 phone number fields, and I run a ValidationError at the Model level using clean:
class Person(models.Model):
personal_phone_mobile = PhoneNumberField()
personal_phone_direct =…
alias51
- 8,178
- 22
- 94
- 166
2
votes
1 answer
Unique together between field and model connected by ForeignKey django
I have two models.
class Post(models.Model):
title = models.CharField(max_length=150)
class Attachment(models.Model):
type = models.CharField(choices=AttachmentChoices.get_choices(), max_length=15)
link = models.URLField()
post =…
user15125625
- 23
- 4
2
votes
0 answers
Django constraints for UniqueConstraint does not work
I have tried to implement constraints for UniqueConstraint for two foreign keys in the Django model. So far it has not been working as expected. Here below is the model definition :
class AssetMember(models.Model):
asset =…
london_utku
- 1,070
- 2
- 16
- 36
2
votes
1 answer
Django `UniqueConstraint` exception handled the same as 'unique=True'
When UniqueConstraint of a model is violated, an exception is raised. How can I make it to behave the same as violation of a field with unique=True?
identifier = models.CharField("id", max_length=30, unique=True, blank=True, null=True,…
aaronn
- 448
- 1
- 6
- 16
2
votes
0 answers
Django Concat cannot be used in AddConstraint
I have a constraint like this
CheckConstraint(
check=Q(full_path__endswith=Concat(Value("/"), F("identifier"), Value("/"))) #
| Q(full_path="/"),
name="path_endswith_identifier_if_not_root",
),
Makemigrations runs fine, but when I try…
Pinna_be
- 4,517
- 2
- 18
- 34
1
vote
1 answer
Django multi-table inheritance - make sure only one child exists (CheckConstraint)
How can I make sure that a parent object has only one child/type?
class Property(...):
class Meta:
abstract = False
class Flat(Property):
pass
class House(Property):
pass
class Land(Property):
pass
I want every property…
Milano
- 18,048
- 37
- 153
- 353
1
vote
1 answer
Django CheckConstraints to check start_date greater than or equal today
from django.db import models
from django.db.models.functions import Now, TruncDay
class Foo(models.Model):
start_date = models.DateTimeField()
end_date = models.DateTimeField()
class Meta:
constraints…
jujube
- 11
- 3
1
vote
1 answer
Constrain unique_together could have conflict with the unique_field in dajngo Class
I would like to know if there is any conflict using the constraint unique_together as well as the parameter unique=true in one of the fields that belong to the array of the unique_together.
I can´t remove the parameter unique=true of my field…
user15854983
- 11
- 1
1
vote
1 answer
Django Model Constraint Condition Using Field From Inherited Class - Is It Possible?
I'd like to use a field from a parent class as a constraint condition in a child class.
models.py
class ParentClass(object):
...
is_public = models.BooleanField(default=False)
class ChildClass(ParentClass):
...
price =…
Jarad
- 17,409
- 19
- 95
- 154
1
vote
0 answers
Django constraint: allowing 1 field to only have a single combination with another field while still alowing historical data
I am trying to create a constraint on my Offer table, which has an offer_id (charfield) and a product_id (foreign key) where an offer_id can only be combined with 1 product. It is not allowed that an offer_id is combined with multiple products.
I…
Mathijs
- 177
- 3
- 18
1
vote
1 answer
Django: How to treat null as equal to everything for uniqueness constraints?
In the title I mean equal to any value, not just to other nulls.
Let's say for the sake of the example that we have a household, with household members (people) and electronic devices. Some electronic devices are personal and belong to one person,…
talz
- 1,004
- 9
- 22
1
vote
0 answers
Why is my model field out of scope in the constraints?
Models.py
class Bug(models.Model):
title = models.CharField(max_length=200)
creator = models.ForeignKey(User, on_delete=models.CASCADE, related_name="creator")
lead = models.ForeignKey(User, default=None, blank=True,…
Dallas Hoekstra
- 11
- 1
1
vote
1 answer
Django unit test constraints
So I have a problem in writing my unit tests for a Check and Unique constraint. Here are the their definition:
# assert that a partner can have only one headquarter
constraints = [
models.UniqueConstraint(
fields=['partner', 'active'],
…
davidm
- 1,570
- 11
- 24
0
votes
1 answer
Django constraint for "field one not in field two for any row"?
Suppose I have a Django model with two fields one and two:
class MyModel(models.Model):
one = models.CharField(max_length=100, unique=True)
two = models.CharField(max_length=100)
unique=True means if I try to put in a row with one="one"…
dfrankow
- 20,191
- 41
- 152
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