Custom columns using Django admin

Question

I have a model Data, associated to a table like this (The model Data is made up of only IntegerField):

subject | year | quarter | sales | ----------------------------------    1    | 2010 |   1     | 20    |    1    | 2010 |   2     | 100   |    1    | 2010 |   3     | 100   |    1    | 2010 |   4     | 20    |    1    | 2011 |   1     | 30    |    1    | 2011 |   2     | 50    |    1    | 2011 |   4     | 40    |    2    | 2010 |   1     | 30    |    2    | 2010 |   2     | 20    |  [..-GO ON this way...] 

I want to have a django-admin table, in read-only having columns (current year = 2011, quarter = 1)

subject | sales current year | sales current quarter | sales last year | sales current quarter last year | ----------------------------------------------------------------------------------------------------------   1     |  110               |  30                   |  240            |  20 [AND SO ON] 

The question is: It is possible do that using django-admin? What's the way out?

Answer 1

You can use methods on your Model or your ModelAdmin as items for list_display. See: https://docs.djangoproject.com/en/dev/ref/contrib/admin/#django.contrib.admin.ModelAdmin.list_display

Since these are methods that might be useful outside the admin, as well, I'd suggest adding them to your Model.

from django.db.models import Sum  class Data(models.Model):     ...      # Method used by `get_current_year_sales` and `get_last_year_sales`     # to stay DRY. Not for use directly in admin.     def get_year_sales(self, year):         qs = self.model._default_manager.filter(year=year)         sales_agg = qs.aggregate(Sum('sales'))         return sales_agg['sales__sum']      # Method used by `get_current_quarter_sales` and `get_last_quarter_sales`     # to stay DRY. Not for use directly in admin.     def get_quarter_sales(self, year, quarter):         qs = self.model._default_manager.filter(year=year, quarter=quarter)         sales_agg = qs.aggregate(Sum('sales'))         return sales_agg['sales__sum']      def get_current_year_sales(self):         return self.get_year_sales(datetime.now().year)     get_current_year_sales.short_description = 'Sales (Current Year)'      def get_last_year_sales(self):         return self.get_year_sales(datetime.now().year-1)     get_last_year_sales.short_description = 'Sales (Last Year)'      def get_current_quarter_sales(self):         # Determine current quarter logic here as `current_quarter`         # `quarter_year` will likely be same as current year here,         # but will need to be calculated for previous quarter         return self.get_quarter_sales(quarter_year, current_quarter)     get_current_quarter_sales.short_description = 'Sales (Current Quarter)'      def get_current_quarter_sales(self):         # Logic here to determine last quarter as `last_quarter`         # Logic to determine what year last quarter was in as `quarter_year`         return self.get_quarter_sales(quarter_year, last_quarter)     get_last_quarter_sales.short_description = 'Sales (Last Quarter)' 

The short_description attribute determines what the admin will show as the row header for these methods. So, once you have all this in place, you need only modify your ModelAdmin's list_display attribute like:

class DataAdmin(admin.ModelAdmin):     ...     list_display = ('subject', 'get_current_year_sales', 'get_last_year_sales', 'get_current_quarter_sales', 'get_last_quarter_sales') 

Answer 2

Something like this should work (untested):

# models.py class Data(models.Model):     year = models.DateField()     sales = models.IntegerField()     # ...      def sales_current_year(self):         return self.model._default_manager.get_queryset().filter(year=2012).annotate(Sum('sales'))   # admin.py  class DataAdmin(admin.ModelAdmin):       list_display = ('sales_current_year',)