CODEWITHSUNDEEP
pythondjangopython-2.7django-models
ChrisDevWard
ChrisDevWard

Reputation: 965

Django filter from within models

I'm trying to setup my django administration page with HighCharts so I can allow admins to visualize some of the data easily.

I can currently get the total number of riders for all objects within the PeopleCount model (totalPeople), but when I try filtering by a StopID (totalPeopleByStop), it breaks.

Here is my models.py, along with the aforementioned methods in the PeopleCount class:

from django.db import models
from django.template.loader import render_to_string

class Vehicle(models.Model):
    VehID = models.AutoField(primary_key=True)
    Title = models.CharField(max_length=40)
    Driver = models.CharField(max_length=25)

def __unicode__(self):
    return self.Title


class Location(models.Model):
    LocID = models.AutoField(primary_key=True)
    VehID = models.ForeignKey('Vehicle')
    Latitude = models.DecimalField(max_digits=10, decimal_places=6)
    Longitude = models.DecimalField(max_digits=10, decimal_places=6)
    Speed = models.DecimalField(max_digits=4, decimal_places=1)

    def __unicode__(self):
       #VehID + LocID Identifier
       return str(self.LocID)


class PeopleCount(models.Model):
    CountID = models.AutoField(primary_key=True)
    StopID = models.ForeignKey('StopLocation')
    VehID = models.ForeignKey('Vehicle')
    LocID = models.ForeignKey('Location')
    Date = models.DateField(auto_now_add=True, blank=False)
    Time = models.TimeField(auto_now_add=True)
    Count = models.IntegerField()

    Date.editable = True
    Time.editable = True

    def totalPeople(self):
        totPeople = 0
        for model in PeopleCount.objects.all():
            totPeople += model.Count
        return totPeople

    def totalPeopleByStop(self, stopname):
        totPeople = 0
        name = stopname
        for model in PeopleCount.objects.filter(StopID=stopname).all():
            totPeople += model.Count
        return totPeople

    def __unicode__(self):
        return str(self.CountID)

    def peoplecount_chart(self):
       totalPeople = self.totalPeople()
       totalRamsey = self.totalPeopleByStop("Ramsey")
       lu = { 'categories' : [self.StopID],\
           'tot_riders' : [self.Count],\
           'tot_riders_at_stop' : [totalPeople]}

       return render_to_string('admin/tracker/peoplecount/peoplecount_chart.html', lu )
     peoplecount_chart.allow_tags = True

class StopLocation(models.Model):
    StopID = models.AutoField(primary_key=True)
    StopName = models.CharField(max_length=40)
    Latitude = models.DecimalField(max_digits=10, decimal_places=6)
    Longitude = models.DecimalField(max_digits=10, decimal_places=6)

    def __unicode__(self):
        #VehID + LocID Identifier
        return str(self.StopName)

There aren't any errors that occur through django or in any logs, so I'm not entirely sure how to get totalPeopleByStop() working correctly.

Upvotes: 1

Views: 107

Answers (1)

schillingt
schillingt

Reputation: 13731

You can do this a little easier with django aggregates.

from django.db.models import Sum


class PeopleCount(models.Model):
   ...

   def totalPeopleByStop(self, stopname):
        return PeopleCount.objects.filter(StopID=stopname).aggregate(
            total_people_by_stop=Sum('Count'))['total_people_by_stop']

Upvotes: 1

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