What you’re after is:

    TestModel.objects.create(testkey_id=1)

In my case `TestModel.objects.create(testkey__id=1)` didn&#39;t work for me so I had to put one underscore instead of two, for example

`TestModel.objects.create(testkey_id=1)`

In `get_or_create` it will fail in get. So to make `get_or_create` work below is the solution:

    TestModel.objects.get_or_create(testkey=TestModel2(id=1))

Reference:
https://code.djangoproject.com/ticket/13915

I have a `text_area` inside a `fields_for`, which is inside a `form_for`.

    &lt;%= day_form.text_area :hatch %&gt;

Is it possible to change the size of the `text_area`? For example: `day_form.text_area size: 5`.

Rails text_area size

I tried to learn the meaning of _arrows_, but I didn&#39;t understand them. 

I used the Wikibooks tutorial. I think Wikibook&#39;s problem is mainly that it seems to be written for somebody who already understands the topic.

Can somebody explain what arrows are and how I can use them?

What are arrows, and how can I use them?

Suppose I have a simple model class like this:

    class TestModel(models.Model):
        testkey = models.ForeignKey(TestModel2)
        ...

When I am creating a TestModel object I have to pass to it an instance of the TestModel2 object to create it:

    testkey =TestModel2.objects.get(id=...)
    TestModel.objects.create(testkey=testkey)

This results in 2 queries to database I suppose, and I have a list of Foreign key IDs that I need to create objects with.

Is it possible to create objects with foreign keys without initially retrieving the foreign key objects?

Django model object with foreign key creation

Suppose I have a simple model class like this:
<pre><code class="hljs language-arduino">class TestModel(models.Model):
 testkey = models.ForeignKey(TestModel2)
 ...
</code></pre>
When I am creating a TestModel object I have to pass to it an instance of the TestModel2 object to create it:
<pre><code class="hljs language-ini">testkey =TestModel2.objects.get(id=...)
TestModel.objects.create(testkey=testkey)
</code></pre>
This results in 2 queries to database I suppose, and I have a list of Foreign key IDs that I need to create objects with.
Is it possible to create objects with foreign keys without initially retrieving the foreign key objects?

I have a model called `Thing` with an attribute called `name`, and I want name to be a char field that&#39;s _only_ 3 characters long.

How do I write a test for that?

    class TestCase1(TestCase):
        def test1(self):
            thing = Thing(name=&#39;1234&#39;)

that test should fail. How do I properly write the test so that the test _passes_ when that object fails?




how to write django test meant to fail?

The table in question contains roughly ten million rows.

    for event in Event.objects.all():
        print event

This causes memory usage to increase steadily to 4 GB or so, at which point the rows print rapidly. The lengthy delay before the first row printed surprised me – I expected it to print almost instantly.

I also tried `Event.objects.iterator()` which behaved the same way.

I don&#39;t understand what Django is loading into memory or why it is doing this. I expected Django to iterate through the results at the database level, which&#39;d mean the results would be printed at roughly a constant rate (rather than all at once after a lengthy wait).

What have I misunderstood?

(I don&#39;t know whether it&#39;s relevant, but I&#39;m using PostgreSQL.)

Why is iterating through a large Django QuerySet consuming massive amounts of memory?

How do I check if a variable is **False** using Django template syntax?

    {% if myvar == False %}

Doesn&#39;t seem to work.

Note that I very specifically want to check if it has the Python value `False`. This variable could be an empty array too, which is *not* what I want to check for.

Django templates: If false?

Before saving model I&#39;m re-size a picture. But how can I check if new picture added or just description updated, so I can skip rescaling every time the model is saved?


    class Model(model.Model):
        image=models.ImageField(upload_to=&#39;folder&#39;)
        thumb=models.ImageField(upload_to=&#39;folder&#39;)
        description=models.CharField()
    
    
        def save(self, *args, **kwargs):
            if self.image:
                small=rescale_image(self.image,width=100,height=100)
                self.image_small=SimpleUploadedFile(name,small_pic)
            super(Model, self).save(*args, **kwargs)

I want to rescale only if new image loaded or image updated, but not when description updated.

Django. Override save for model

I&#39;ve got these models in my Django project:

    class Area(models.Model):
        name = models.CharField(max_length=100, primary_key=True)
        def __unicode__(self):
            return self.name
    class Place(models.Model):
        id = models.IntegerField(primary_key=True) 
        name = models.CharField(max_length=100, primary_key=True)
        area = models.ManyToManyField(Area,related_name=&#39;area&#39;)

How can I show the Place&#39;s area name(s) in my template? Currently I have:
 
    {% for place in places %}
        Name: {{ place.name }}, Area: {{ place.area}}
    {% endfor %}

which gives:
 
    Area: &lt;django.db.models.fields.related.ManyRelatedManager object at 0x10435a3d0&gt;

And `{{ place.area}}` is just blank. Can anyone help?

Django: show a ManyToManyField in a template?

    EMP_CHOICES = (
             (0,&#39;-- Select --&#39;),
             (1,&#39;Good&#39;),
             (2,&#39;Average&#39;),
         )

    class EMPFeedback(models.Model):
         user_choices = models.IntegerField(choices=EMP_CHOICES)

If the value stored in the db as 1 for user_choices how to print the corresponding user_choices corresponding value (i.e. 1==GOOD)

    fb = EMPFeedback.objects.get(id=1)
    print fb.user_choices  # prints 1
    print fb.user_choices.EMP_CHOICES 


Django print choices value

Django automatically creates an id field as primary key.

Now I need to get the object by this id.


    object = Class.objects.filter() 

How to write this filter?

Django database query: How to get object by id?

**models.py:**

    class Person(models.Model):
        name = models.CharField(max_length=200)
        CATEGORY_CHOICES = (
            (&#39;M&#39;, &#39;Male&#39;),
            (&#39;F&#39;, &#39;Female&#39;),
        )
        gender = models.CharField(max_length=200, choices=CATEGORY_CHOICES)
        to_be_listed = models.BooleanField(default=True)
        description = models.CharField(max_length=20000, blank=True)

**views.py:**

    def index(request):
        latest_person_list2 = Person.objects.filter(to_be_listed=True)
        return object_list(request, template_name=&#39;polls/schol.html&#39;,
                           queryset=latest_person_list, paginate_by=5)

On the template, when I call `person.gender`, I get `&#39;M&#39;` or `&#39;F&#39;` instead of `&#39;Male&#39;` or `&#39;Female&#39;`.


How to display the value (`&#39;Male&#39;` or `&#39;Female&#39;`) instead of the code (`&#39;M&#39;`/`&#39;F&#39;`)?



Django: Display Choice Value

Is it possible to refresh the state of a django object from database? I mean behavior roughly equivalent to:

    new_self = self.__class__.objects.get(pk=self.pk)
    for each field of the record:
        setattr(self, field, getattr(new_self, field))


**UPDATE:** Found a reopen/wontfix war in the tracker: http://code.djangoproject.com/ticket/901.
Still don&#39;t understand why the maintainers don&#39;t like this.

Content Type	Original Author	Original Content on Stackoverflow
Question	dragoon	View Question on Stackoverflow
Solution 1 - Django	sneeu	View Answer on Stackoverflow
Solution 2 - Django	Zohab Ali	View Answer on Stackoverflow
Solution 3 - Django	Dhruvil Amin	View Answer on Stackoverflow

Django model object with foreign key creation

Django Problem Overview

Django Solutions

Solution 1 - Django

Solution 2 - Django

Solution 3 - Django

What are arrows, and how can I use them?

Rails text_area size

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