So I have predefined database structure like this:
User:
id
User_1:
user_=ForeignKey(User)
User_2:
user_1=ForeignKey(User_1)
Something:
owner=ForeignKey(User_2)
users=ManyToMany(User_2)
Well, I need to fill the table Something. Short story is that from front end I receive the ids of model User but to store I need User_2. One way I see right now is to write custom create method is serializer and do all manually.
Are there other ways to solve it?
And is it correct to use serializers.PrimaryKeyRelatedField to deal with ForeignKey when payload has next format?
{
"user": 1
}
Related
The frontend sends the json in an array.
I received the value with difficulty as shown in ex) below.
ex)
applier_phone = data.get('phone')[0]
applier_name = data.get('name')[0]
applier_birth = data.get('birth')[0]
applier_gender = data.get('gender')[0]
But I want to get the value using Serializer.
In this case, which method of Serializer do I need to customize?
I don't think the best solution would be to modify the Serializer in itself. Rather i would suggest to modify the Json Object so the serializer detects it as by the initial schema od your Model.
This will let the Serializer still be usable for multiple case and instances.
If you still want to take the first approach i would suggest you may intervene in any of the .create() .update() , or even validate() methods for re-structuring your JSON object.
It is my first question here, after reading the similar questions I did not find what I need, thanks for your help.
I am creating a fairly simple API but I want to use best practices at the security level.
Requirement: There is a table in SQL Server with +5 million records that I should ONLY allow READ (all fields) and UPDATE (one field). This is so that a data scientist consumes data from this table and through a predictive model (I think) can assign a value to each record.
For this I mainly need 2 things:
That only one field is updated despite sending all the fields of the table in the Json (I think I have achieved it with my serializer).
And, where I have problems, is in disabling the creation of new records when updating one that does not exist.
I am using an UpdateAPIView to allow trying to allow a bulk update using a json like this (subrrogate_key is in my table and I use lookup_field to:
[
{
"subrrogate_key": "A1",
"class": "A"
},
{
"subrrogate_key": "A2",
"class": "B"
},
{
"subrrogate_key": "A3",
"class": "C"
},
]
When using the partial_update methods use update and this perform_update and this finally calls save and the default operation is to insert a new record if the primary key (or the one specified in lookup_field) is not found.
If I overwrite them, how can I make a new record not be inserted, and only update the field if it exists?
I tried:
Model.objects.filter (subrrogate_key = ['subrrogate_key']). Update (class = ['class])
Model.objects.update_or_create (...)
They work fine if all the keys in the Json exist, because if a new one comes they will insert (I don't want this).
P.S. I use a translator, sorry.
perform_update will create a new record if you passed a serializer that doesn't have an instance. Depending on how you wrote your view, you can simply check if there is an instance in the serializer before calling save in perform_update to prevent creating a new record:
def perform_update(self, serializer):
if not serializer.instance:
return
serializer.save()
Django implements that feature through the use of either force_update or update_fields during save().
https://docs.djangoproject.com/en/3.2/ref/models/instances/#forcing-an-insert-or-update
https://docs.djangoproject.com/en/3.2/ref/models/instances/#specifying-which-fields-to-save
https://docs.djangoproject.com/en/3.2/ref/models/instances/#saving-objects
In some rare circumstances, it’s necessary to be able to force the
save() method to perform an SQL INSERT and not fall back to doing an
UPDATE. Or vice-versa: update, if possible, but not insert a new row.
In these cases you can pass the force_insert=True or force_update=True
parameters to the save() method.
model_obj.save(force_update=True)
or
model_obj.save(update_fields=['field1', 'field2'])
I'm using Simple Form, and I have a few fields that are not associated with my model. I found using this fake field option to be a good solution:
https://github.com/plataformatec/simple_form/wiki/Create-a-fake-input-that-does-NOT-read-attributes
I thought this was cleaner than adding an attr_accessor value for my fields, and it works great for text input fields. I'm hoping to accomplish the same thing with a Select Field.
I found this thread, but I couldn't find anything else:
https://github.com/plataformatec/simple_form/issues/747
Has anyone found a similar option for a Fake Select Input? Thanks!
Assuming you'll use that "fake select" for UI purposes (probably as a mean to modify the form fields to present the user using Javascript?) and you don't want to deal with the value in the controller, you could just use select_tag with any field name, instead of the simple_form f.input. The value will be sent to the server, but it will be outside the model params, so you can just ignore it in the controller.
If I misunderstood your question, please clarify.
If your just trying to get the name='whatever' instead of having name='model[whatever]' I've found it easiest to just specify the name attribute in input_html { name: 'whatever', id: 'whatever' } hash which over rides the default model[attribute].
Otherwise you could create a fake_select_input.rb which would be similar to fake_input.rb but obviously use a select_tag instead and do something like as: :fake_select
I was wondering what is the correct approach,
Do I create HiddenInput fields in my ModelForm and from the
View I pass in the primaryKey for the models I am about to edit into
the hiddenInput fields and then grab those hiddenInput fields from
the AJAX script to use it like this?
item.load(
"/bookmark/save/" + hidden_input_field_1,
null,
function () {
$("#save-form").submit(bookmark_save);
}
);
Or is there is some more clever way of doing it and I have no idea?
Thanks
It depends upon how you want to implement.
The basic idea is to edit 1. you need to get the existing instance, 2. Save provided information into this object.
For #1 you can do it multiple ways, like passing ID or any other primary key like attribute in url like http://myserver/edit_object/1 , Or pass ID as hidden input then you have to do it through templates.
For #2, I think you would already know this. Do something like
inst = MyModel.objects.get(id=input_id) # input_id taken as per #1
myform = MyForm(request.POST, instance=inst)
if myform.is_valid():
saved_inst = myform.save()
I just asked in the django IRC room and it says:
since js isn't processed by the django template engine, this is not
possible.
Hence the id or the object passed in from django view can't be accessed within AJAX script.
I want to use django's admin filter on the list page.
The models I have are something like this:
class Location(model):
name = CharField()
class Inquiry(Model):
name = CharFiled()
location = ManyToManyField(Location)
Now I want to filter Inquiries, to display only those that contain relation to specific Location object. If I use
class InqAdmin(ModelAdmin):
list_filter = ['location', ]
admin.site.register(Inquiry, InqAdmin)
the admin page displays me the list of all Locations and allows to filter.
What I would like to get, is to get list of only those locations that have some Inquiries in relation to them (so I don't ever get the empty list result after filtering).
How can this be done?
You could create a custom manager for Locations that only returns Locations that have an Inquiry associated with them. If you make this the default manager, the admin will use it.
Only caveat is that you'll need create another manager that returns all Locations and use that in the rest of your app whenever you want to retrieve Locations that don't have an associated Inquiry.
The managers section in the Django docs is quite good, and should be all you need to get this set up.
EDIT:
sienf brings up a good point. Another way to accomplish this would be to define a subclass of django.contrib.admin.SimpleListFilter, and write the queryset method to filter out Inquiries with empty Locations. See https://docs.djangoproject.com/en/dev/ref/contrib/admin/#django.contrib.admin.ModelAdmin.list_filter