I have below PostDetail Model defined
from wagtail.core.models import Page
class PostDetail(Page):
template = "Post_Detail.html"
body = RichTextField(blank=True)
After python manage.py migrate, when I examine the database table of PostDetail, I only see 2 columns (attributes) and did not see all those attributes (title / owner / first_published_at etc according to the source code here.) which are supposed to be inherited from Page model.
Anything I missed out or did wrong ?
Wagtail's Page model uses multi-table inheritance - the shared fields from the base class are stored in a record on the wagtailcore_page table, while the fields specific to a subclass are in a separate table with a link back to the base wagtailcore_page record.
Having all of the 'core' fields in a single table makes it possible to retrieve (for example) the child pages of a given page, without having to search in every table for every possible page type.
Related
I have a subclass of Wagtail Page class that has field of django ManyToManyField type. When I try to create a new instance of my page object, I get a list of objects that the the ManyToManyField points to and I am able select multiple items. However, after creating that page when I try to edit the same page, it seems no data got saved for the ManyToMany field. I know in Django ModelAdmin one have to override the save_related() to save ManyToMany field data. Is there a similar method for the Wagtail Page model?
You should define the field as a ParentalManyToManyField relation, as per the example here: http://docs.wagtail.io/en/v1.13.1/getting_started/tutorial.html#categories
This is a variant of ManyToManyField which is able to keep track of the relation in memory, allowing it to work in situations such as previewing and saving as draft (where it doesn't get saved to the normal database records).
I was able to use the 'after_edit_page' and 'after_create_page' hooks to save the data for the page's ManyToMany fields.
I have a single page application with AngularJs and Django. On my main page, I get all the forms needed when loading the page. BUT, some fields are dynamically updated.
Let's say I have
class Model1(models.Model):
pass
class Model2(models.Model):
model_1 = models.ForeignKey(Model1)
forms:
class Model2Form(forms.ModelForm):
class Meta:
model = Model2
fields = ('model_1', )
My SPA allows me to create instances of Model1 (without reloading the page). I know how to filter the options shown and dynamically add the new instances in the select field BUT, doing so, when the html is first rendered, before angular magic takes place and filter the available options, I get the queryset made by django which is by default model.objects.all(). All right, I'd like to display none of that. I tried to add in the init of my function:
self.fields['model_1'].queryset = Model1.objects.none()
and indeed no option is displayed in the select field when the form is first rendered but then, I can't validate my form, I get the error: Select a valid choice. That choice is not one of the available choices. (obviously, it had no option available due to the queryset.none() )
I'd really like not to load forms when called but doing it when my page first load. Is there any option to help me do so?
Cheers guyz,
Keep rocking
You need to specify that the model_1 field of Model2 can be null, as specified here:
Allow null in foreign key to user. Django
model_1 = models.ForeignKey(Model1, null=True, blank=True, default = None)
I find out how to handle that problem. It is quite stupid, I did not give you all the parameters of the problem.
The forms are rendered on load but when I validate it, it goes through a CRUD operation and an OTHER form is initialized at this point which will handle the data I'm sending. So I can override the queryset in the init of that (second) form based on some extra kwargs to differentiate between the form I'm using for the first rendering and the form to handle my data.
No need to make any field nullable or add extra validation.
Hope I'm clear enough. Cheers
I made a search for this for about 4 days and I couldn't find anything by any means that describe this step by step. I had found this article which describe how to add Email field to UserProfile table, the first step in this tutorial requires you to open DefaultConnection Database but I don't know how to do that.
So my question is:
1- how to add extra attributes in UserProfile database (using WebSecurity.InitializeDatabaseConnection method).
2- What If I want to make my own database and let MVC to create UserProfile table with the extra attributes ?
If you have any questions let me know in the comments below.
EDIT:
I tried to add these extra attributes to UserProfile Class which I believe that it follows code first technique, after that I had changed the connection string to my own database then after building the project Tables (UserProfile, webpages_Membership, webpages_OAuthMembership, etc..) created successfully but with no extra attribute that I already added to UserProfile class before building.
If you use Entity Framework do that:
First you must enable migrations if you didn't did it.
After that look for 'ApplicatinUser' class and add property that you want(e.g FullName).
So I got the tables you can see in the image below:
.
What I would like to do is to create a relationship so that each user (of django auth_user) will be enrolled(or able to enrol) to exactly one "course" so that he will be able to see next events for his modules.
Do I have to create another table and place 2 foreign keys or this is a way to do it in 'php' and it's more simple with Django? I was suggested to create 'student' model inheriting from 'User' with extended behavior and one to many relationship on auth. I tried to do that but unfortunately had not results since I'm really new to Django & Python.
If every auth_user (or auth.User) will be or have the opportunity to be enrolled on a course I would create a 'user profile' model that has a 1-to-1 relationship with the django User model. You can store additional User data in this model, including what course they are enrolled on. See https://docs.djangoproject.com/en/dev/topics/auth/customizing/#extending-the-existing-user-model for more details but here is an example:
class UserProfile(models.Model):
user = models.OneToOneField('auth.User')
course = models.ForeignKey('courseapp.Course', null=True)
You would probably need to create a signal that gets fired each time an auth.User object is saved, such that if it is the first time that User object has been saved, it automatically creates the UserProfile:
from django.contrib.auth.models import User
from django.db.models.signals import post_save
from yourusersapp.models import UserProfile
def create_user_profile(sender, instance, created, **kwargs):
# Automatically creates a UserProfile on User creation.
if created:
UserProfile.objects.create(user=instance)
post_save.connect(create_user_profile, sender=User)
When you query a User object, you can then reference the User object's profile like:
user_object.userprofile
You could then create a Course object and link the user_object indirectly via its UserProfile to that Course:
course = Course.objects.create(name='course_name', next_field='whatever')
user_profile = user_object.userprofile
userprofile.course = course
userprofile.save()
Now you have a user object with a UserProfile that is linked to only 1 course. Many users can be on the same course, but a user can only be on 1 course. You can also reference all users on a particular course like:
course = Course.objects.get(name='course_name')
course_users = course.userprofile_set.all()
HTH
I think that you can go about this one of two ways.
Extend the User model. 'Student' would probably be a good name for your new model. It would have a OneToOne relationship with 'User', and a ForeignKey relationship with 'Course'. It can store any other information that is applicable to students only. Documentation for how to do that can be found here https://docs.djangoproject.com/en/1.6/topics/auth/customizing/#extending-the-existing-user-model
Create a custom User model that has a ForeignKey relationship with Course. This approach is a bit more complicated, but yields a slightly cleaner end result. Documentation for that is here. https://docs.djangoproject.com/en/1.6/topics/auth/customizing/#substituting-a-custom-user-model
Sorry if it seems like I'm just sending you to the Django docs, but both of those sections are well written and should explain things pretty clearly. If you'd like to post another question with example code we can try and see why your original attempt at extending the User model didn't work. By the way, your "Student" model shouldn't have to inherit from the User model in order to extend it.
I have a table in my database called "Task". Task has the following fields:
- ID
- Description
- AssignedUserID
- TaskTypeID
I am accessing this table through a class that was created automatically after I used an ADO.NET Entity Data Model. I can load and show the fields mentioned above in a DataGrid in my Silverlight application. However, AssignedUserID and TaskTypeID are not very descriptive. So I decided to create a stored procedure that gets the tasks and the user and task type names through their respective lookup tables. This is where the problem lies.
I want to create some custom properties in the automatically generated "Task" class. The custom properties would be named "AssignedUserName" and "TaskType". I then want to make these properties available to my Silverlight client. However, I cannot seem to figure out how to get them exposed to my Silverlight client.
Can someone help?
Thank you
If your EDM is in the same project as the DomainService you can do this:
create a partial class on the Entity type, and add your calculated property in there.
name the file **.shared.cs
it will then be auto-shared with the client/Silverlight code.
Edit:
I was assuming that you could do this calculation in app logic rather than use an sp, which seems more straightforward to me.
If you do use an SP, you'll need to use the Function Import feature in the designer to map the SP to a function in the EDM. This function can then return entities, with properties mapped however you like.
An easier way would be to just use the object model: Have Task.AssignedUser and Task.TaskType objects off of your Task class. Map these to lookup tables in your db. This will work out-of-the box (assuming the Id's are FK's to those lookup tables).
So, a couple options:
use app-logic--properties in a partial class to return the descriptions
use the object model driven by FKs to lookup tables, then just access Task.AssignedUser.Name or Task.TaskType.Description
use a function import to access the SP and map the returned values to entity properties
1 or 2 being the best options IMHO.
Another approach might be to update your EF model to include the lookup tables, add Associations between the tables, add [Include]s in the (auto-gen'd) metadata class and let EF and RIA do it for you. Maybe.