```
Asset.objects.filter( project__name__contains=&quot;Foo&quot; )
```

This has been possible since the `queryset-refactor` branch landed pre-1.0.  [Ticket 4088][1] exposed the problem.  This should work:

    Asset.objects.filter(
        desc__contains=filter,
        project__name__contains=&quot;Foo&quot;).order_by(&quot;desc&quot;)

The [Django Many-to-one documentation][2] has this and other examples of following Foreign Keys using the Model API.


  [1]: http://code.djangoproject.com/ticket/4088
  [2]: https://docs.djangoproject.com/en/stable/topics/db/examples/many_to_one/#many-to-one-relationships


    student_user = User.objects.get(id=user_id)
    available_subjects = Subject.objects.exclude(subject_grade__student__user=student_user) # My ans
    enrolled_subjects = SubjectGrade.objects.filter(student__user=student_user)
    context.update({&#39;available_subjects&#39;: available_subjects, &#39;student_user&#39;: student_user, 
                    &#39;request&#39;:request, &#39;enrolled_subjects&#39;: enrolled_subjects})

In my application above, i assume that once a student is enrolled, a subject  SubjectGrade instance will be created that contains the subject enrolled and  the student himself/herself.

Subject and Student User model is a Foreign Key to the SubjectGrade Model.

In  &quot;available_subjects&quot;, i excluded all the subjects that are already enrolled by the current student_user   by checking all subjectgrade instance that has  &quot;student&quot; attribute as the current student_user

PS. Apologies in Advance if you can&#39;t still understand because of my explanation. This is the best explanation i Can Provide. Thank you so much 

Are there any options to get the last insert id of a new record in CodeIgniter?

    $last_id = $this-&gt;db-&gt;insert(&#39;tablename&#39;,
        array(&#39;firstcolumn&#39; =&gt; &#39;value&#39;,
        &#39;secondcolumn&#39; =&gt; &#39;value&#39;)
    );

Considering the table consits of fields id (autoincrement) firstcolumn and secondcolumn.

This way you can use the insert id in the following code.


CodeIgniter activerecord, retrieve last insert id?

I saw an [answer to a question][1] here that helps restore a deleted file in git.

The solution was

    git checkout &lt;deleting_commit&gt;^ -- &lt;deleted_file_path&gt;

What does the caret character (`^`) do? I’ve seen it elsewhere doing very useful things in git. It’s magical. Someone please spoil it for me and tell me what it does?

  [1]: https://stackoverflow.com/questions/953481/restore-a-deleted-file-in-a-git-repo/1113140#1113140

What does the caret (^) character mean in Git?

I&#39;m trying to filter a table in Django based on the value of a particular field of a `ForeignKey`.

For example, I have two models:

    class Asset(models.Model):
        name = models.TextField(max_length=150)
        project = models.ForeignKey(&#39;Project&#39;)

    class Project(models.Model):
        name = models.TextField(max_length=150)

I&#39;d like to filter my asset list based on the name of the associated project.

Currently, I am performing **two** queries:


    project_list = Project.objects.filter(name__contains=&quot;Foo&quot;)
    asset_list = Asset.objects.filter(desc__contains=filter,
                                      project__in=project_list).order_by(&#39;desc&#39;)

I&#39;m wondering if there is a way to specify this kind of filtering in the main query?


Django - filtering on foreign key properties

I'm trying to filter a table in Django based on the value of a particular field of a <code>ForeignKey</code>.
For example, I have two models:
<pre><code class="hljs language-ini">class Asset(models.Model):
 name = models.TextField(max_length=150)
 project = models.ForeignKey('Project')

class Project(models.Model):
 name = models.TextField(max_length=150)
</code></pre>
I'd like to filter my asset list based on the name of the associated project.
Currently, I am performing two queries:
<pre><code class="hljs language-ini">project_list = Project.objects.filter(name__contains="Foo")
asset_list = Asset.objects.filter(desc__contains=filter,
 project__in=project_list).order_by('desc')
</code></pre>
I'm wondering if there is a way to specify this kind of filtering in the main query?

I&#39;ve already defined a model and created its associated database via `manager.py syncdb`. Now that I&#39;ve added some fields to the model, I tried `syncdb` again, but no output appears. Upon trying to access these new fields from my templates, I get a &quot;No Such Column&quot; exception, leading me to believe that syncdb didn&#39;t actually update the database. What&#39;s the right command here?

update django database to reflect changes in existing models

In my Django app, I need to start running a few periodic background jobs when a user logs in and stop running them when the user logs out, so I am looking for an elegant way to

 1. get notified of a user login/logout
 2. query user login status

From my perspective, the ideal solution would be

 1. a signal sent by each `django.contrib.auth.views.login` and `... views.logout`
 2. a method `django.contrib.auth.models.User.is_logged_in()`, analogous to `... User.is_active()` or `... User.is_authenticated()`

Django 1.1.1 does not have that and I am reluctant to patch the source and add it (not sure how to do that, anyway).

As a temporary solution, I have added an `is_logged_in` boolean field to the UserProfile model which is cleared by default, is set the first time the user hits the landing page (defined by `LOGIN_REDIRECT_URL = &#39;/&#39;`) and is queried in subsequent requests. I added it to UserProfile, so I don&#39;t have to derive from and customize the builtin User model for that purpose only.

I don&#39;t like this solution. If the user explicitely clicks the logout button, I can clear the flag, but most of the time, users just leave the page or close the browser; clearing the flag in these cases does not seem straight forward to me. Besides (that&#39;s rather data model clarity nitpicking, though), `is_logged_in` does not belong in the UserProfile, but in the User model.

Can anyone think of alternate approaches ?

Django: signal when user logs in?

Trying to use a very simple form to upload a file into a new class instance. I am expecting to have both files in `request.FILES` but it&#39;s empty. I am on the bundled dev server.

Been stuck here and went through all related questions.

    wayfinder_map.media_file = request.FILES[&#39;media_file&#39;] 

generates

&gt; MultiValueDictKeyError: &quot;Key &#39;media_file&#39; not found in MultiValueDict:
&gt; {}&gt;&quot;

**model**

    class WayfinderMap(models.Model):
        &quot;&quot;&quot; Way-finding Map Config&quot;&quot;&quot;
    
    
        media_file = models.FileField(upload_to=&quot;maps&quot;, null=True, blank=True) 
        wall_file = models.FileField(upload_to=&quot;maps_data&quot;, null=True, blank=True) 
**view**

    @login_required
    def create_map(request, form_class=WayfinderMapForm, template_name=&quot;wayfinder/map/create.html&quot;):
    wayfinder_map_form = form_class(request.user, request.POST or None, request.FILES)
    
        if wayfinder_map_form.is_valid():
            wayfinder_map = wayfinder_map_form.save(commit=False)
            wayfinder_map.media_file = request.FILES[&#39;media_file&#39;]
            wayfinder_map.data_file = request.FILES[&#39;data_file&#39;]
            wayfinder_map.creator = request.user
            wayfinder_map.save()
        return HttpResponseRedirect(wayfinder_map.get_absolute_url())
    
    return render_to_response(template_name, {
        &quot;wayfinder_map_form&quot;: wayfinder_map_form,
    }, context_instance=RequestContext(request))

**template**

    &lt;form enctype=&quot;multipart/form-data&quot; class=&quot;uniForm&quot; id=&quot;wayfinder_map_form&quot; method=&quot;POST&quot; action=&quot;&quot;&gt;
            &lt;fieldset class=&quot;inlineLabels&quot;&gt;
                {{ wayfinder_map_form|as_uni_form }}
                &lt;div class=&quot;form_block&quot;&gt;
                    &lt;input type=&quot;hidden&quot; name=&quot;action&quot; value=&quot;create&quot; /&gt;
                    &lt;input type=&quot;submit&quot; value=&quot;{% trans &#39;create&#39; %}&quot;/&gt;
                &lt;/div&gt;
            &lt;/fieldset&gt;
        &lt;/form&gt;

Empty Request.FILES with Django Upload forms

I&#39;m running into a paradigm problem here. I don&#39;t know whether I should store money as a Decimal(), or if I should store it as a string and convert it to a decimal myself. My reasoning is this:

**PayPal requires 2 decimal places**, so if I have a product that is 49 dollars even, PayPal wants to see 49.00 come across the wire. Django&#39;s DecimalField() doesn&#39;t set a decimal amount. It only stores a maximum decimal places amount. So, if you have 49 in there, and you have the field set to 2 decimal places, it&#39;ll still store it as 49. I know that Django is basically type casting when it deserializes back from the database into a Decimal (since Databases don&#39;t have decimal fields), so I&#39;m not completely concerned with the speed issues as much as I am with the design issues of this problem. I want to do what&#39;s best for extensibility.

Or, better yet, does anyone know how to configure a django DecimalField() to always format with the TWO_PLACES formatting style.

Django: How should I store a money value?

I have a model which has a date time field:

```python
date = models.DateField(_(&quot;Date&quot;), default=datetime.now())
```

When I check the app in the built in django admin, the `DateField` also has the time appended to it, so that if you try to save it an error is returned. How do I make the default just the date? (`datetime.today()` isn&#39;t working either)

Django DateField default options

I&#39;m trying to find a way to implement both a custom `QuerySet` and a custom `Manager` without breaking DRY.  This is what I have so far:

    class MyInquiryManager(models.Manager):
        def for_user(self, user):
            return self.get_query_set().filter(
                        Q(assigned_to_user=user) |
                        Q(assigned_to_group__in=user.groups.all())
                    )
    
    class Inquiry(models.Model):   
        ts = models.DateTimeField(auto_now_add=True)
        status = models.ForeignKey(InquiryStatus)
        assigned_to_user = models.ForeignKey(User, blank=True, null=True)
        assigned_to_group = models.ForeignKey(Group, blank=True, null=True)
        objects = MyInquiryManager()

This works fine, until I do something like this:

    inquiries = Inquiry.objects.filter(status=some_status)
    my_inquiry_count = inquiries.for_user(request.user).count()

This promptly breaks everything because the `QuerySet` doesn&#39;t have the same methods as the `Manager`.  I&#39;ve tried creating a custom `QuerySet` class, and implementing it in `MyInquiryManager`, but I end up replicating all of my method definitions.

I also found [this snippet][1] which works, but I need to pass in the extra argument to `for_user` so it breaks down because it relies heavily on redefining `get_query_set`.

Is there a way to do this without redefining all of my methods in both the `QuerySet` and the `Manager` subclasses?


  [1]: http://adam.gomaa.us/blog/2009/feb/16/subclassing-django-querysets/

Custom QuerySet and Manager without breaking DRY?

Is there a way to extend the built-in Django Group object to add additional attributes similar to the way you can extend a user object? With a user object, you can do the following: 

    class UserProfile(models.Model):
        user = models.OneToOneField(User)

and add the following to the settings.py file

    AUTH_PROFILE_MODULE = &#39;app.UserProfile&#39;

which gets you:

    profile = User.objects.get(id=1).get_profile()


Is there any equivalent to this approach for extending a group? If not, is there an alternative approach I can take?

How do I extend the Django Group model?

I have two models `A` and `B`. All `B` objects have a foreign key to an `A` object. Given a set of `A` objects, is there anyway to use the ORM to get a set of `B` objects containing the most recent object created for each `A` object.

Here&#39;s an simplified example:

```python3
class Bakery(models.Model):
    town = models.CharField(max_length=255)

class Cake(models.Model):
    bakery = models.ForeignKey(Bakery, on_delete=models.CASCADE)
    baked_at = models.DateTimeField()
```

So I&#39;m looking for a query that returns the most recent cake baked in each bakery in Anytown, USA.

Django Query That Get Most Recent Objects From Different Categories

How can I retrieve the last record in a certain queryset?

Get last record in a queryset

I have these models:

    def Foo(Models.model):
        size = models.IntegerField()
        # other fields
        
        def is_active(self):
             if check_condition:
                  return True
             else:
                  return False
    
    def Bar(Models.model):
         foo = models.ForeignKey(&quot;Foo&quot;)
         # other fields

Now I want to query Bars that are having active Foo&#39;s as such:

    Bar.objects.filter(foo.is_active())

I am getting error such as

    SyntaxError at /
    (&#39;non-keyword arg after keyword arg&#39;

How can I achieve this?

Django, query filtering from model method

I have a model similar to the following:

    class Review(models.Model):
        venue = models.ForeignKey(Venue, db_index=True)
        review = models.TextField()  
        datetime_created = models.DateTimeField(default=datetime.now)


I&#39;d like to query the database to get the total number of reviews for a venue grouped by day.  The MySQL query would be:

    SELECT DATE(datetime_created), count(id) 
    FROM REVIEW 
    WHERE venue_id = 2
    GROUP BY DATE(datetime_created);

What is the best way to accomplish this in Django?  I could just use

    Review.objects.filter(venue__pk=2)

and parse the results in the view, but that doesn&#39;t seem right to me.

Content Type	Original Author	Original Content on Stackoverflow
Question	Fraser Graham	View Question on Stackoverflow
Solution 1 - Django	Fragsworth	View Answer on Stackoverflow
Solution 2 - Django	Michael Greene	View Answer on Stackoverflow
Solution 3 - Django	Kinowe	View Answer on Stackoverflow

Django - filtering on foreign key properties

Django Problem Overview

Django Solutions

Solution 1 - Django

Solution 2 - Django

Solution 3 - Django

What does the caret (^) character mean in Git?

CodeIgniter activerecord, retrieve last insert id?

Attributions