Question

I am following this part of the ‘django by example’ tutorial. Now when I go to /admin/todo/datetime/ and click on Add date time I get this error:

Exception Type: Exception at /admin/todo/datetime/add/
Exception Value: <class 'todo.models.Item'> has no ForeignKey to <class 'todo.models.DateTime'>

My code is pretty much identical(except that I have the import statements included):

from django.db import models
from django.contrib import admin

class DateTime(models.Model):
    datetime = models.DateTimeField(auto_now_add = True)
    def __unicode__(self):
       return unicode(self.datetime)

class Item(models.Model):
    name = models.CharField(max_length = 60)
    created = models.DateTimeField(auto_now_add = True)
    priority = models.IntegerField(default = 0)
    difficulty = models.IntegerField(default = 0)
    done = models.BooleanField(default = False)

class ItemAdmin(admin.ModelAdmin):
    list_display = ["name", "priority", "difficulty", "created", "done"]
    search_fields = ["name"]

class ItemInline(admin.TabularInline):
    model = Item

class DateAdmin(admin.ModelAdmin):
    list_display = ["datetime"]
    inlines = [ItemInline]

admin.site.register(Item, ItemAdmin)
admin.site.register(DateTime, DateAdmin)

I looked at similar S.O. threads but I can’t figure out from there what is going wrong here.
(Btw, I use django 1.3 while django 1.2 is used in the turorial)

Answer 1

Your models don’t match those in the tutorial. Your Item.created is a DateTimeField while their Item.created is a ForeignKey to the DateTime model.

# From http://lightbird.net/dbe/todo_list.html#adding-multiple-items

class DateTime(models.Model):
    datetime = models.DateTimeField(auto_now_add=True)
    def __unicode__(self):
        return unicode(self.datetime)

class Item(models.Model):
    name = models.CharField(max_length=60)
    created = models.ForeignKey(DateTime)
    priority = models.IntegerField(default=0)
    difficulty = models.IntegerField(default=0)
    done = models.BooleanField(default=False)