I have a relationship follow as:
class Question(models.Model):
qid = models.PositiveIntegerField(primary_key=True)
content = models.CharField(max_length=128)
class Answer(models.Model):
answerid = models.PositiveIntegerField(primary_key=True)
content = models.CharField(max_length=128)
question = models.ForeignKey(Question)
class AnswerInline(admin.StackedInline):
model = Answer
readonly_fields = ('answerid',)
extra = 0
class QuestionAdmin(admin.ModelAdmin):
inlines = [AnswerInline]
exclude = ('id')
list_display = ('content',)
admin.site.register(Question,QuestionAdmin)
Suppose I have a question namely A and I haven't any answer for this question yet.
So, when I add an answer of A. It's ok. However, I try to add an other answer, system output an error MultiValueDictKeyError:
"Key 'oam_answer_set-0-answerid' not found in QueryDict:...
Because both of 'qid' and 'answerid' are not an AutoField. So, when I save an object, django admin can not insert a new row into database (missing primary key).
The AutoField is declared an IntegerField. However, I would like the field type of primary key is PositiveIntegerField. For that reason, how can I customize an AutoField?
Thanks
Try registering the Answer model with the admin i.e.
...
admin.site.register(Answer)
at the bottom of the admin.py. You are using fields on the inline (specifically readonly_fields) that are inherited from ModelAdmin, but you might not have registered that model.
Related
I am using depth = 1 on my serializer to show details of a foreign key field. However, it is also showing details of another foreign key field which I don't really need. How do I show the details of one field but not the other one?
Just for your reference
Suppose you have three models:
class User(model.Model):
username = model.CharField('username', max_length=10)
class Question(model.Model):
title = models.CharField('title', max_length=10)
class Answer(model.Model):
user = model.ForeignKey(User)
question = model.ForeignKey(Question)
body = model.TextField('the answer body')
And you need to serialise Answer, with showing the detail of Question, but not showing the detail of User, then you could define your serialisers like that:
class QuestionSerializer(serializers.ModelSerializer):
class Meta:
model = Question
exclude = []
class AnswerSerializer(serializers.ModelSerializer):
question = QuestionSerializer(many=False, read_only=True)
class Meta:
model = Answer
exclude = []
when you serialise Answer with AnswerSerializer, you will notice that question field is serialise at the same time, however user field is still an integer without serialising.
If you need to serialise a foreign key, you can define a field in the serializer explicitly, and the field name equal to the field name in model, and the value is equal to Foreign key model serializer. When the model is serialise, Answer in this case, the foreign key field, question for this case, will be "expanded" with QuestionSerializer, and other foreign key fields still keep the origin foreign key value, user in this case, if you haven't explicitly defined a serializer field in the serializer.
Hope it would help.
I imported my (PHP) old site's database tables into Django. By default it created a bunch of primary key fields within the model (since most of them were called things like news_id instead of id).
I just renamed all the primary keys to id and removed the fields from the model. The problem then came specifically with my News model. New stuff that I add doesn't appear in the admin. When I remove the following line from my ModelAdmin, they show up:
list_display = ['headline_text', 'news_category', 'date_posted', 'is_sticky']
Specifically, it's the news_category field that causes problems. If I remove it from that list then I see my new objects. Now, when I edit those items directly (hacking the URL with the item ID) they have a valid category, likewise in the database. Here's the model definitions:
class NewsCategory(models.Model):
def __unicode__(self):
return self.cat_name
#news_category_id = models.IntegerField(primary_key=True, editable=False)
cat_name = models.CharField('Category name', max_length=75)
cat_link = models.SlugField('Category name URL slug', max_length=75, blank=True, help_text='Used in URLs, eg spb.com/news/this-is-the-url-slug/ - generated automatically by default')
class Meta:
db_table = u'news_categories'
ordering = ["cat_name"]
verbose_name_plural = "News categories"
class News(models.Model):
def __unicode__(self):
return self.headline_text
#news_id = models.IntegerField(primary_key=True, editable=False)
news_category = models.ForeignKey('NewsCategory')
writer = models.ForeignKey(Writer) # todo - automate
headline_text = models.CharField(max_length=75)
headline_link = models.SlugField('Headline URL slug', max_length=75, blank=True, help_text='Used in URLs, eg spb.com/news/this-is-the-url-slug/ - generated automatically by default')
body = models.TextField()
extra = models.TextField(blank=True)
date_posted = models.DateTimeField(auto_now_add=True)
is_sticky = models.BooleanField('Is this story featured on the homepage?', blank=True)
tags = TaggableManager(blank=True)
class Meta:
db_table = u'news'
verbose_name_plural = "News"
You can see where I've commented out the autogenerated primary key fields.
It seems like somehow Django thinks my new items don't have news_category_ids, but they definitely do. I tried editing an existing piece of news and changing the category and it worked as normal. If I run a search for one of the new items, it doesn't show up, but the bottom of the search says "1 News found", so something is going on.
Any tips gratefully received.
EDIT: here's my ModelAdmin too:
class NewsCategoryAdmin(admin.ModelAdmin):
prepopulated_fields = {"cat_link": ("cat_name",)}
list_display = ['cat_name', '_cat_count']
def _cat_count(self, obj):
return obj.news_set.count()
_cat_count.short_description = "Number of news stories"
class NewsImageInline(admin.TabularInline):
model = NewsImage
extra = 1
class NewsAdmin(admin.ModelAdmin):
prepopulated_fields = {"headline_link": ("headline_text",)}
list_display = ['headline_text', 'news_category', 'date_posted', 'is_sticky'] #breaking line
list_filter = ['news_category', 'date_posted', 'is_sticky']
search_fields = ['headline_text']
inlines = [NewsImageInline]
The answer you are looking for I think would lie in the SQL schema that you altered and not in the django models.
It could probably have something to do with null or blank values in the news_category_id, or news that belongs to a category that doesn't exist in the news_category. Things I'd check:
You have renamed the primary key on the News category from news_category_id to id. Does the foreign key on the News also map to news_category_id and not anything else?
Are all the values captured in the news.news_category also present in news_category.id
Also, as an aside, I don't see any reason why you need to rename the primary keys to id from something that they already are. Just marking them primary_key=True works just fine. Django provides you a convenient alias pk to access a model's integer primary key, irrespective of what the name of the field actually is.
I have created two models out of an existing legacy DB , one for articles and one for tags that one can associate with articles:
class Article(models.Model):
article_id = models.AutoField(primary_key=True)
text = models.CharField(max_length=400)
class Meta:
db_table = u'articles'
class Tag(models.Model):
tag_id = models.AutoField(primary_key=True)
tag = models.CharField(max_length=20)
article=models.ForeignKey(Article)
class Meta:
db_table = u'article_tags'
I want to enable adding tags for an article from the admin interface, so my admin.py file looks like this:
from models import Article,Tag
from django.contrib import admin
class TagInline(admin.StackedInline):
model = Tag
class ArticleAdmin(admin.ModelAdmin):
inlines = [TagInline]
admin.site.register(Article,ArticleAdmin)
The interface looks fine, but when I try to save, I get:
Warning at /admin/webserver/article/382/
Field 'tag_id' doesn't have a default value
This can also happen if you have a disused field in your database that doesn't allow NULL.
The problem was that in the DB, tag_id wasn't set as an autoincrement field.
What solved this issue in my case was disabling STRICT_TRANS_TABLES SQL mode which was enabled by default.
Using the following code:
class Organization(models.Model):
name = models.CharField(max_length="100",)
alias = models.SlugField()
...
class Division(Organization):
parent_org = models.ForeignKey(Organization)
class Meta:
unique_together=['parent_org', 'alias']
...
Trying to syncdb give me this error:
Error: One or more models did not validate:
organizations.division: "unique_together" refers to alias. This is not in the
same model as the unique_together statement.
Any help is appreciated,
Thanks,
Eric
This is by design. Reading the documentation for the unique_together option, it states that:
It's used in the Django admin and is enforced at the database level.
If you look at the table that a subclass creates, you'll see that it doesn't actually have the fields that its parent has. Instead, it gets a soft Foreign Key to the parent table with a field name called [field]_ptr_id, where [field] is the name of the table you're inheriting from excluding the app name. So your division table has a Primary Foreign Key called organization_ptr_id.
Now because unique_together is enforced at the database level using the UNIQUE constraint, there's no way that I know of for the database to actually apply that to a field not in the table.
Your best bet is probably through using Validators at your business-logic level, or re-thinking your database schema to support the constraint.
Edit: As Manoj pointed out, you could also try using Model Validators such as validate_unique.
[Model] Validators would work for you. Perhaps simplest, though, would be to use:
class BaseOrganization(models.Model):
name = models.CharField(max_length="100",)
alias = models.SlugField()
class Meta:
abstract = True
class Organization(BaseOrganization):
pass
class Division(BaseOrganization):
parent_org = models.ForeignKey(Organization)
class Meta:
unique_together=['parent_org', 'alias']
Note: as with your current code, you could not have subdivisions of divisions.
This is a solution I recently used in Django 1.6 (thanks to Manoj Govindan for the idea):
class Organization(models.Model):
name = models.CharField(max_length="100",)
alias = models.SlugField()
...
class Division(Organization):
parent_org = models.ForeignKey(Organization)
# override Model.validate_unique
def validate_unique(self, exclude=None):
# these next 5 lines are directly from the Model.validate_unique source code
unique_checks, date_checks = self._get_unique_checks(exclude=exclude)
errors = self._perform_unique_checks(unique_checks)
date_errors = self._perform_date_checks(date_checks)
for k, v in date_errors.items():
errors.setdefault(k, []).extend(v)
# here I get a list of all pairs of parent_org, alias from the database (returned
# as a list of tuples) & check for a match, in which case you add a non-field
# error to the error list
pairs = Division.objects.exclude(pk=self.pk).values_list('parent_org', 'alias')
if (self.parent_org, self.alias) in pairs:
errors.setdefault(NON_FIELD_ERRORS, []).append('parent_org and alias must be unique')
# finally you raise the ValidationError that includes all validation errors,
# including your new unique constraint
if errors:
raise ValidationError(errors)
This does not strictly apply the question but is very closely related; unique_together will work if the base class is abstract. You can mark abstract model classes as such using:
class Meta():
abstract = True
This will prevent django from creating a table for the class, and its fields will be directly included in any subclasses. In this situation, unique_together is possible because all fields are in the same table.
https://docs.djangoproject.com/en/1.5/topics/db/models/#abstract-base-classes
I had similar challenge when trying to apply unique_together to a permission group created by a given client.
class ClientGroup(Group):
client = models.ForeignKey(Client, on_delete=models.CASCADE)
is_active = models.BooleanField()
class Meta():
# looking at the db i found a field called group_ptr_id.
# adding group_ptr did solve the problem.
unique_together = ('group_ptr', 'client', 'is_active')
Django has a unique_for_date property you can set when adding a SlugField to your model. This causes the slug to be unique only for the Date of the field you specify:
class Example(models.Model):
title = models.CharField()
slug = models.SlugField(unique_for_date='publish')
publish = models.DateTimeField()
What would be the best way to achieve the same kind of functionality for a non-DateTime field like a ForeignKey? Ideally, I want to do something like this:
class Example(models.Model):
title = models.CharField()
slug = models.SlugField(unique_for='category')
category = models.ForeignKey(Category)
This way I could create the following urls:
/example/category-one/slug
/example/category-two/slug
/example/category-two/slug <--Rejected as duplicate
My ideas so far:
Add a unique index for the slug and categoryid to the table. This requires code outside of Django. And would the built-in admin handle this correctly when the insert/update fails?
Override the save for the model and add my own validation, throwing an error if a duplicate exists. I know this will work but it doesn't seem very DRY.
Create a new slug field inheriting from the base and add the unique_for functionality there. This seems like the best way but I looked through the core's unique_for_date code and it didn't seem very intuitive to extend it.
Any ideas, suggestions or opinions on the best way to do this?
What about unique_together?
class Example(models.Model):
title = models.CharField()
slug = models.SlugField(db_index=False)
category = models.ForeignKey(Category)
class Meta:
unique_together = (('slug','category'),)
# or also working since Django 1.0:
# unique_together = ('slug','category',)
This creates an index, but it is not outside of Django ;) Or did I miss the point?