Django multiple models in one template using forms

Question

I m building a support ticket tracking app and have a few models I d like to create from one page  Tickets belong to a Customer via a ForeignKey  Notes belong to Tickets via a ForeignKey as well  I d like to have the option of selecting a Customer  that s a whole separate project  OR creating a new Customer  then creating a Ticket and finally creating a Note assigned to the new ticket   Since I m fairly new to Django  I tend to work iteratively  trying out new features each time  I ve played with ModelForms but I want to hide some of the fields and do some complex validation  It seems like the level of control I m looking for either requires formsets or doing everything by hand  complete with a tedious  hand-coded template page  which I m trying to avoid   Is there some lovely feature I m missing  Does someone have a good reference or example for using formsets  I spent a whole weekend on the API docs for them and I m still clueless  Is it a design issue if I break down and hand-code everything

User · Answer

I just was in about the same situation a day ago, and here are my 2 cents:

1) I found arguably the shortest and most concise demonstration of multiple model entry in single form here: http://collingrady.wordpress.com/2008/02/18/editing-multiple-objects-in-django-with-newforms/ .

In a nutshell: Make a form for each model, submit them both to template in a single <form>, using prefix keyarg and have the view handle validation. If there is dependency, just make sure you save the "parent" model before dependant, and use parent's ID for foreign key before commiting save of "child" model. The link has the demo.

2) Maybe formsets can be beaten into doing this, but as far as I delved in, formsets are primarily for entering multiples of the same model, which may be optionally tied to another model/models by foreign keys. However, there seem to be no default option for entering more than one model's data and that's not what formset seems to be meant for.

User · Answer

According to Django documentation  inline formsets are for this purpose   Inline formsets is a small abstraction layer on top of model formsets  These simplify the case of working with related objects via a foreign key    See https   docs djangoproject com en dev topics forms modelforms  inline-formsets

User · Answer

I currently have a workaround functional  it passes my unit tests   It is a good solution to my opinion when you only want to add a limited number of fields from other models   Am I missing something here    class UserProfileForm ModelForm       def   init   self  instance None   args    kwargs             Add these fields from the user object          fields     first name    last name    email              Retrieve initial  current  data from the user object          initial   model to dict instance user   fields  if instance is not None else              Pass the initial data to the base         super UserProfileForm  self    init   initial  initial  instance instance   args    kwargs            Retrieve the fields from the user model and update the fields with it         self fields update fields for model User   fields        class Meta          model   UserProfile         exclude     user         def save self   args    kwargs           u   self instance user         u first name   self cleaned data  first name           u last name   self cleaned data  last name           u email   self cleaned data  email           u save           profile   super UserProfileForm  self  save  args   kwargs          return profile

User · Answer

I very recently had the some problem and just figured out how to do this  Assuming you have three classes  Primary  B  C and that B C have a foreign key to primary      class PrimaryForm ModelForm           class Meta              model   Primary      class BForm ModelForm           class Meta              model   B             exclude     primary         class CForm ModelForm            class Meta              model   C             exclude     primary         def generateView request           if request method     POST     If the form has been submitted                primary form   PrimaryForm request POST  prefix    primary               b form   BForm request POST  prefix    b               c form   CForm request POST  prefix    c               if primary form is valid   and b form is valid   and c form is valid      All validation rules pass                     print  all validation passed                      primary   primary form save                       b form cleaned data  primary     primary                     b   b form save                       c form cleaned data  primary     primary                     c   c form save                       return HttpResponseRedirect   viewer  s      primary name               else                      print  failed           else              primary form   PrimaryForm prefix    primary               b form   BForm prefix    b               c form   Form prefix    c        return render to response  multi model html           primary form   primary form        b form   b form        c form   c form             This method should allow you to do whatever validation you require  as well as generating all three objects on the same page  I have also used javascript and hidden fields to allow the generation of multiple B C objects on the same page

User · Answer

I want to hide some of the fields and do some complex validation    I start with the built-in admin interface    Build the ModelForm to show the desired fields  Extend the Form with the validation rules within the form   Usually this is a clean method   Be sure this part works reasonably well    Once this is done  you can move away from the built-in admin interface   Then you can fool around with multiple  partially related forms on a single web page   This is a bunch of template stuff to present all the forms on a single page   Then you have to write the view function to read and validated the various form things and do the various object saves      Is it a design issue if I break down and hand-code everything    No  it s just a lot of time for not much benefit

User · Answer

This really isn t too hard to implement with ModelForms  So lets say you have Forms A  B  and C  You print out each of the forms and the page and now you need to handle the POST   if request POST        a valid   formA is valid       b valid   formB is valid       c valid   formC is valid         we do this since  and  short circuits and we want to check to whole page for form errors     if a valid and b valid and c valid          a   formA save           b   formB save commit False          c   formC save commit False          b foreignkeytoA   a         b save           c foreignkeytoB   b         c save     Here are the docs for custom validation

User · Answer

The MultiModelForm from django-betterforms is a convenient wrapper to do what is described in Gnudiff s answer  It wraps regular ModelForms in a single class which is transparently  at least for basic usage  used as a single form  I ve copied an example from their docs below     forms py from django import forms from django contrib auth import get user model from betterforms multiform import MultiModelForm from  models import UserProfile  User   get user model    class UserEditForm forms ModelForm       class Meta          fields     email     class UserProfileForm forms ModelForm       class Meta          fields     favorite color     class UserEditMultiForm MultiModelForm       form classes              user   UserEditForm           profile   UserProfileForm           views py from django views generic import UpdateView from django core urlresolvers import reverse lazy from django shortcuts import redirect from django contrib auth import get user model from  forms import UserEditMultiForm  User   get user model    class UserSignupView UpdateView       model   User     form class   UserEditMultiForm     success url   reverse lazy  home        def get form kwargs self           kwargs   super UserSignupView  self  get form kwargs           kwargs update instance                user   self object               profile   self object profile                     return kwargs

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