This question is somewhat linked to a question I asked previously:
Generating and submitting a dynamic number of objects in a form with Django
I'm wondering, if I've got separate default values for each form within a formset, am I able to pre-populate the fields? For instance, a form requiring extra customer information to be pre-populated with the users names? In cases like adding an email field to an already existing table, and updating many of them at once.
Does Django provide an easy way to do this?
Pass in a list of dicts which contain the default values you want to set for each form:
http://docs.djangoproject.com/en/dev/topics/forms/formsets/#using-initial-data-with-a-formset
Related
I am creating a web-app w/ Flask + Flask-WTF that has CRM-like features as a project. My current database (MongoDB) structure is I have:
Users who can login,
People who are assigned to users, and
Records who are assigned to people.
People have various fields to be filled out (Name, Phone Number, Email, etc).
I want Users to be able to create custom fields for people. I am trying to plan out how to implement this from a database design perspective. My initial thoughts are to:
For each field created, add a new field without a value for each People assigned to the user.
Use a for-loop to dynamically create the form class by looping through each field-value in my database and excluding non-required ones.
Use a for-loop to dynamically output the web form by looping through each field-value in my database and excluding non-required ones.
Another idea I have is:
For each field created, add the custom field, with a parentRecord equal to the User ID to a new MongoDB collection.
Use a for-loop to create the form class & web form dynamically, but I wouldn't need to exclude non-required ones as the only fields in the collection would be the custom ones, and wouldn't include any special data points that don't get displayed.
So my questions are:
Will my ideas above work?
Which one is better?
Is there a better way?
I decided to create a customfields MongoDB collection that has a parentRecord as the User.
I faced a few challenges:
I had to dynamically create a form via flask WTF. I ended up using wtforms_dynamic_fields to accomplish this. I then used a for-loop to dynamically generate each form in Jinja. I simply queried the customfields DB where the parentRecord matched the logged in User, and then created custom fields based upon the values saved in customfields.
The second issue I faced was getting the data from the submitted form and then building a MongoDB-friendly list to insert a new record with when creating new record. This was accomplished by using request.form.items() and iterating through them and using list.update() to add all of my required fields to a list.
I have a project in which I need to add a custom form field to a form (or formset) in which depending on the choice in the custom field selected, an integer in a database field is changed.
I can't seem to find any examples or prior questions which imply how to modify a database field via a custom field. I suspect it is done by overwriting the save() function in a ModelForm but cannot work out how.
Any advice on solving this problem would be greatly appreciated.
An Example:
My class has an integer field which is the field that needs updating.
class Employee(Model):
years = models.IntegerField()
However this field cannot be updated as it is, instead what is needed is a ChoiceField (I think) with different options that, depending on the selection, changes the field with a +1, -1, or reset to zero.
As previously mentioned this is where I imagine some work with the save() function needs to be done but am unsure.
As a side note in case this affects what can be done, eventually this ModelForm will need to be used in a formset so I can edit multiple objects on one page.
I want to create a dynamic admin site, that based on if the field is blank or not will show that field. So I have a model that has a set number of fields, but for each individual entry will not contain all of the fields in my model and I want to exclude based on if that field is blank.
I have a unique bridge identifier, that correlates to each bridge, and then all of the various different variables that describe the bridge.
I have it set up now that the user will go to a url with the unique bridgekey and then this will create an entry of that bridge. So (as i am testing on my local machine) it would be like localhost/home/brkey and that code in my views.py that corresponds to that url is
However, not every bridge is the same and I have a lot more variables that I would like to include in my model but for now I am just testing on two : prestressed_concrete_deck and reinforced_concrete_coated_bars. What I want is to dynamically create the admin site to not display the prestressed_concrete_deck variable if that field is blank. So instead of displaying all of the variables on the admin site, I want to only display those variables if that bridge has that part, and to not display anything if the field is blank.
Another possible solution to the problem would be to get that unique identifier over to my admins.py. I cant figure out either how to get that individual key over as then I could query in the admins.py. If i knew how to access the bridgekey, I could just query in my admins.py dynamically. So how would I access the brkey for that entry in my admins.py (Something like BridgeModel.brkey ?)
I have tried several different things in my admin.py and have tried the comments suggestion of overwriting the get_fields() method in my admin class, but I am probably syntactically wrong and I am kind of confused what the object it takes exactly is. Is that the actual entry? Or is that the individual field?
Just override the get_fields method in your ModelAdmin class.
You can check the obj is passed as function argument so you can check which fields are empty. The function needs to return a tuple so, you would check if field1 is None and then return (field1, field2, field3) or (field2, field3) depending on the value of field1.
I was using Django 1.6 which did not support overriding the get_fields method. Updated to 1.7 and this method worked perfectly.
I'm a newbie and right now I'm using Django forms to show some fields. One of these fields is a ModelChoiceField this show correctly model data, but I don´t know how I can fill a CharField later of select a option in the ModelChoiceField.
How I can make send the value of option selected for obtain the data that i need for later show this in a CharField, this is possible make directly from a djangoForm or do I need a new view to return the value?
There are two ways to achieve what you want I think:
Provide an initial value for your form value.
Bind your form to some data.
See this related stack overflow to provide initial values.
See Django's documentation on forms for binding data. There are two kinds of form states: bound and unbound. To create a bound form, you just need to create an instance of your form with some data: MyForm({'data-key1': 'data-value1', ...}).
There exist two ways in Django to process the several forms in one request:
Form prefix
Form sets
In which use case is each one preferable?
In my specific case, the form lists the fields for an object to be updated from a diff. For each field, an action can be defined (like "update value", "keep value"). The page contains forms for several objects.
If you have several different forms classes with same input names, like a PetForm and an OwnerForm with both a name input in the same page, then you have to use a prefix as explained in the documentation you linked.
If you want to have the same form class repeated, ie. to render a table of TicketForm, then you can use Formsets directly: Formsets use the form prefix feature internally and you don't have to worry about it.