How do I know if django model instance was modified?

Question

I've got a code like that:

# ...
obj = Model.objects.get(pk=2342)
if foo:
    obj.foo = 'bar'
if bar:
    obj.bar = 'baz'
obj.save()

Is there a good way to find out if the model instance was modified in order to prevent saving it each time the code runs?

Answer 1

The typical pattern is to do something like:

model = Model.objects.get(pk=2342)
dirty = False
if foo:
    model.foo = 'bar'
    dirty = True
if bar:
    model.bar = 'baz'
    dirty = True

if dirty:
    model.save()