Django - storing logical tests as records

I'm working on a Gran Turismo 5 Django application. Here's a very simplified data model:

class Event(models.Model):
    name = models.CharField(max_length=256, unique=True)

class EventCriteria(models.Model):
    name = models.CharField(max_length=256, unique=True)
    events = models.ManyToManyField(Event)
    test = ???

class Country(models.Model):
    name = models.CharField(max_length=256, unique=True)

class Make(models.Model):
    name = models.CharField(max_length=256, unique=True)
    country = models.ForeignKey(Country)

class Car(models.Model):
    name = models.CharField(max_length=256, unique=True)
    make = models.ForeignKey(Make)

class Setup(models.Model):
    name = models.CharField(max_length=256, uni开发者_JAVA技巧que=True)
    car = models.ForeignKey(Car)
    horsepower = models.IntegerField()

For example, a given event might have the criteria 'Country = Italy'. When applied against the model above, that would require a test like the following:

setup.car.make.country.name == u'Italy'

Does anyone have a good framework for how I might structure the EventCriteria model (especially the 'test' field or fields') to make a) storing these tests and b) applying them as filters in future views possible?

Thanks,

Mike

---

It's not clear on why your "test" isn't a simple boolean field. The question is confusing. I'm assuming that really want a persistent filter, since that's often requested.

A Django filter is a dictionary.

SomeModel.objects.filter( column=value, column__contains=value )

SomeModel.objects.filter( **{'column':value, 'column__contains':value} )

You can do this to persist your "test".

1. Convert your "filter" expression to a dictionary.

2. JSON-encode the dictionary as a BLOB

3. Save it.

You can apply your test as follows.

1. Get the filter BLOB

2. JSON-decode the dictionary

3. Use the dictionary in a filter for the appropriate class.