Django form to query database (models)

Question

So I want to create a super basic form with a single input field which will be used to query my database.

My model (models.py) is as follows:

from django.db import models

class Book(models.Model):
    uid = models.IntegerField(primary_key=True)
    title = models.CharField(max_length=30)
    class Meta:
        db_table = u'books'

forms.py:

from django import forms
from myapp.models import Book

class EnterIDForm(forms.form):
book_id = forms.CharField()
# add a custom clean function to validate that the user input
#  is a valid book ID
def clean_book_id(self):
    try:
        book_id = int(self.cleaned_data["book_id"])
    except:
        book_id = None

    if book_id and Book.objects.filter(uid=book_id).count():
        return book_id
    else:
        raise forms.ValidationError("Please enter a valid book ID number.")

views.py:

from django.shortcuts import render_to_response
from myapp.models import Book

def form_view(request):
    if request.method == "POST":
        # the user has submitted the form, see if we have a book
        book_id_form = EnterIDForm(request.POST) # instantiate our form class with the user data
        if book_id_form.is_valid():
            # if our form is valid, then we have a book_id that works:
            the_book = Book.objects.get(uid=book_id_form.cleaned_data["book_id"])
                return render_to_response("book_template.html", { "the_book": the_book }, context_instance=RequestContext(request))
        # if the form wasn't valid, it will fall through to the other return statement.
    else:
        # If the user didn't submit a form, instantiate a blank one.
        book_id_form = EnterIDForm()
    return render_to_response("form_template.html", { "book_id_form": book_id_form }, context_instance=RequestContext(request))

I want the input field to collect the "uid" from the user and display the all of the data from the Book model instance where uid is some book in the database.

I have an understanding of how the form is tied in with the view, and later templates, but I just cannot seem to get it to work.

I've endlessly searched the Django site and many other resources for an example I can learn from, but nothing.

Anyone mind helping me out?

Thanks.

As Aamir said, some of the code you tried out already may help us find where is that you're having problems. — asermax, Jan 08 '13 at 23:14
Anthony, edit your question with the form code please, and the view that's supposed to process it. — Josh Smeaton, Jan 09 '13 at 00:51
Why are you removing the content of your questions and replacing it with .... ? — markus, Jan 24 '13 at 23:00

Dan Hoerst · Answer 1 · 2013-01-09T04:42:42.090

10

You can do a simple search here. You do not need any POST calls or form creation. However, if you want to create a form this should still point you in the correct direction.

Try something like this:

search.html:

<form method="get" action="/search/">
  Search Notecards:<input type="text" name="q" id="id_q" value="{{ query }}"/>
  <input type="submit" value="Search" />
</form>

views.py:

from myapp.models import Book
from django.template import RequestContext
from django.shortcuts import render_to_response

def search(request):
    query = request.GET.get('q')
    try:
        query = int(query)
    except ValueError:
        query = None
        results = None
    if query:
        results = Book.objects.get(uid=query)
    context = RequestContext(request)
    return render_to_response('results.html', {"results": results,}, context_instance=context)

results.html:

{% if results %}
  {% for result in results %}
    {{ result.uid }}
    {{ result.xxxx }}
    {{ result.xxxx }}
  {% endfor %}
{% else %}
    <h3 class='error'>Please enter a valid UID</h3>
    <form method="get" action="/search/">
      Search Notecards:<input type="text" name="q" id="id_q" value="{{ query }}"/>
      <input type="submit" value="Search" />
    </form>
{% endif %}

edited Jan 09 '13 at 04:42

answered Jan 09 '13 at 04:27

Dan Hoerst

6,222
2
38
51

What is the exact query that you are passing to the search box? This is a type error so it will not hit the except block. The except block is excepting value errors. Can you edit your original post with how you implemented the search box in your template and the search view. – Dan Hoerst Jan 09 '13 at 14:02
1

You would need to set up a default view - for example `home`. This could be very simple and would load the search.html (the search box). Upon entering a query in the search box, you would load your search view. It sounds like you are going directly to the search view - resulting in `q` equaling `None`. I highly suggest working through the Django tutorial. It's very good. Once you have that tutorial app set up, you can add the suggestions above to the app and see how they function. Then you can reuse the pieces that you need for your app. https://docs.djangoproject.com/en/dev/intro/tutorial01/ – Dan Hoerst Jan 09 '13 at 15:08
This code doesn't work for me, error is `Exception Value: local variable 'results' referenced before assignment`. My form action is post, but I can't even get there because your method has no initial view. – ian-campbell Nov 29 '14 at 23:25

Django form to query database (models)

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