Weather App Tutorial. Part 2 of 5. Models

This is the second part of my tutorial how to make a weather app. This time I will show you how to create the models and set up the admin.

Open the models.py file in the climate_change directory and enter the following:

# -*- coding: UTF-8 -*-
from django.db import models
from django.utils.translation import ugettext_lazy as _
from django.conf import settings

class Location(models.Model):
    name = models.CharField(_("name"), max_length=200)
    location_id = models.CharField(
        _("location ID"),
        max_length=20,
        help_text=_("Location IDs can be retrieved from URLs of weather "
            "at specific cities at Yahoo! Weather, e.g. GMXX0008 from "
            "http://weather.yahoo.com/forecast/GMXX0008.html"),
        )
    
    class Meta:
        verbose_name=_("location")
        verbose_name_plural=_("locations")
    
    def __unicode__(self):
        return self.name

class WeatherLog(models.Model):
    location = models.ForeignKey(Location, verbose_name=_("location"))
    timestamp = models.DateTimeField(_("timestamp"))
    temperature = models.IntegerField(_("temperature (C°)"))
    humidity = models.IntegerField(_("humidity (%)"))
    wind_speed = models.DecimalField(
         _("wind speed (km/h)"),
         max_digits=5,
         decimal_places=2,
         )
    visibility = models.DecimalField(
         _("visibility (km)"),
         max_digits=5,
         decimal_places=2,
         )
    
    class Meta:
        verbose_name=_("weather log")
        verbose_name_plural=_("weather logs")
        ordering = ("-timestamp",)
    
    def __unicode__(self):
        return "%s @ %s" % (
            self.location.name,
            self.timestamp.strftime("%Y-%m-%dT%H:%M"),
            )

The models are created. Now let's create the database schema for them.

python manage.py syncdb

Also in this step when asked, I created a superuser called "demo" to be able to access django-contributed administration. Let's try it out. We'll need to add a file admin.py to climate_change with this content:

# -*- coding: utf-8 -*-
from django.db import models
from django.contrib import admin

Location = models.get_model("climate_change", "Location")
WeatherLog = models.get_model("climate_change", "WeatherLog")

admin.site.register(Location)
admin.site.register(WeatherLog)

Then uncomment admin related lines in urls.py of the project:

# -*- coding: utf-8 -*-
from django.conf.urls.defaults import *
from django.contrib import admin
admin.autodiscover()

urlpatterns = patterns("",
    (r"^admin/", include(admin.site.urls)),
    )

Finally, run the development server and check if the models really work.

python shell runserver
# now you can go to http://127.0.0.1:8000/admin/ in a browser

Yes! Everything works as expected for now. I will add my current location and its ID in Yahoo! Weather to the database. For me it's Berlin, Germany and the ID is GMXX0008. I found the ID in the URL of the page showing the weather for Berlin.



Tomorrow I will show you how to import weather details from Yahoo!