Python/Django TangoWithDjango Models and Databases

I'm currently following http://www.tangowithdjango.com and I'm trying to populate an existing DB with populate_rango.py. When I create the new categories, I'm trying to get the views and likes to be populated with the following:

Python: 128, 64 Django: 64, 32 Other Frameworks: 32, 16

In my admin panel, it keeps showing 0's for both views and likes for all three categories.

Can someone show me what I'm doing incorrectly with the code below?


from django.db import models class Category(models.Model): name = models.CharField(max_length=128, unique=True) views = models.IntegerField(default=0) likes = models.IntegerField(default=0) def __unicode__(self): return self.name class Page(models.Model): category = models.ForeignKey(Category) title = models.CharField(max_length=128) url = models.URLField() views = models.IntegerField(default=0) def __unicode__(self): return self.title


import os import sys def populate(): python_cat = add_cat('Python', 128, 64) add_page(cat=python_cat, title="Official Python Tutorial", url="http://docs.python.org/2/tutorial/") add_page(cat=python_cat, title="How to Think like a Computer Scientist", url="http://www.greenteapress.com/thinkpython/") add_page(cat=python_cat, title="Learn Python in 10 Minutes", url="http://www.korokithakis.net/tutorials/python/") django_cat = add_cat("Django", 64, 32) add_page(cat=django_cat, title="Official Django Tutorial", url="https://docs.djangoproject.com/en/1.5/intro/tutorial01/") add_page(cat=django_cat, title="Django Rocks", url="http://www.djangorocks.com/") add_page(cat=django_cat, title="How to Tango with Django", url="http://www.tangowithdjango.com/") frame_cat = add_cat("Other Frameworks", 32, 16) add_page(cat=frame_cat, title="Bottle", url="http://bottlepy.org/docs/dev/") add_page(cat=frame_cat, title="Flask", url="http://flask.pocoo.org") # Print out what we have added to the user. for c in Category.objects.all(): for p in Page.objects.filter(category=c): print "- {0} - {1}".format(str(c), str(p)) def add_page(cat, title, url, views=0): p = Page.objects.get_or_create(category=cat, title=title, url=url, views=views)[0] return p def add_cat(name, views, likes): c = Category.objects.get_or_create(name=name, views=views, likes=likes)[0] return c # Start execution here! if __name__ == '__main__': print "Starting Rango population script..." os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'tango_with_django_project.settings') from rango.models import Category, Page populate()


""" Django settings for tango_with_django_project project. For more information on this file, see https://docs.djangoproject.com/en/dev/topics/settings/ For the full list of settings and their values, see https://docs.djangoproject.com/en/dev/ref/settings/ """ # Build paths inside the project like this: os.path.join(BASE_DIR, ...) import os BASE_DIR = os.path.dirname(os.path.dirname(__file__)) PROJECT_PATH = os.getcwd() # Quick-start development settings - unsuitable for production # See https://docs.djangoproject.com/en/dev/howto/deployment/checklist/ # SECURITY WARNING: keep the secret key used in production secret! SECRET_KEY = '@&v@6mq6b-4(97c8s^4g((t-&%k&@hi08u$x0w+(mnhre08m!=' # SECURITY WARNING: don't run with debug turned on in production! DEBUG = True TEMPLATE_DEBUG = True ALLOWED_HOSTS = [] # Application definition INSTALLED_APPS = ( 'django.contrib.admin', 'django.contrib.auth', 'django.contrib.contenttypes', 'django.contrib.sessions', 'django.contrib.messages', 'django.contrib.staticfiles', 'rango', ) MIDDLEWARE_CLASSES = ( 'django.contrib.sessions.middleware.SessionMiddleware', 'django.middleware.common.CommonMiddleware', 'django.middleware.csrf.CsrfViewMiddleware', 'django.contrib.auth.middleware.AuthenticationMiddleware', 'django.contrib.messages.middleware.MessageMiddleware', 'django.middleware.clickjacking.XFrameOptionsMiddleware', ) ROOT_URLCONF = 'tango_with_django_project.urls' WSGI_APPLICATION = 'tango_with_django_project.wsgi.application' # Database # https://docs.djangoproject.com/en/dev/ref/settings/#databases DATABASES = { 'default': { 'ENGINE': 'django.db.backends.sqlite3', 'NAME': os.path.join(BASE_DIR, 'db.sqlite3'), } } # Internationalization # https://docs.djangoproject.com/en/dev/topics/i18n/ LANGUAGE_CODE = 'en-us' TIME_ZONE = 'UTC' USE_I18N = True USE_L10N = True USE_TZ = True # Static files (CSS, JavaScript, Images) # https://docs.djangoproject.com/en/dev/howto/static-files/ STATIC_PATH = os.path.join(PROJECT_PATH,'static') STATIC_URL = '/static/' # You may find this is already defined as such. STATICFILES_DIRS = ( STATIC_PATH, ) TEMPLATE_PATH = os.path.join(PROJECT_PATH, 'templates') TEMPLATE_DIRS = ( # Put strings here, like "/home/html/django_templates" or "C:/www/django/templates". # Always use forward slashes, even on Windows. # Don't forget to use absolute paths, not relative paths. TEMPLATE_PATH, ) MEDIA_URL = '/media/' MEDIA_ROOT = os.path.join(PROJECT_PATH, 'media')


I didn't know we needed to complete the exercises of CH5 when doing CH6, luckily I came across your question and this helped me get the desired output I wanted from the index.html.

I haven't done any work with the admin side of things though, but it looks like your error is here:


frame_cat = add_cat("Other Frameworks", 32, 16)


def add_cat(name, views, likes): c = Category.objects.get_or_create(name=name, views=views, likes=likes)[0] return c

You need to make the views=0 & likes=0 in this line: def add_cat(name, views, likes):

Then you need to change this:

frame_cat = add_cat("Other Frameworks", 32, 16) to this:

frame_cat = add_cat("Other Frameworks", views=32, likes=16)

Also, you will have a database called DATABASE_PATH (or at least that is what mine is called). You need to <strong>delete</strong> this and run:

python manage.py syncdb

& then just to make sure it worked, I ran:

python populate_rango.py

When you got the error in the admin section, did you first check the /rango page to see if you were getting the correct output? Chances are, you were also either getting an error like me or your categories weren't displaying (I could be wrong though on your output).

I think my solution will display the views and likes now. Try it and let me know.


The following worked for me, when added to populate_rango.py -

def add_cat(name, views, likes): c = Category.objects.get_or_create(name=name)[0] c.views = views c.likes = likes c.save() return c

The difference might be due to c.save()


The following worked for me. I have no idea whether it will cause issues in later chapters, but it allowed the populate_rango.py script to run.

Changes to <strong>populate_rango.py</strong>

def populate(): python_cat = add_cat("Python", views=128, likes=64) django_cat = add_cat("Django", views=64, likes=32) frame_cat = add_cat("Other Frameworks", views=32, likes=16)


def add_cat(name, views=0, likes=0): c = Category.objects.get_or_create(name=name, views=views, likes=likes)[0] return c

That resulted in a database IntegrityError so I edited the View fields in my Category and Page classes to ensure they aren't unique:

Changes to <strong>models.py</strong>

class Category(models.Model): views = models.IntegerField(default=0, unique=False) class Page(models.Model): views = models.IntegerField(default=0, unique=False)

Finally, I deleted the database and ran

python manage.py syncdb


python populate_rango.py


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