Good way for a Revision Controllled Model? - Django

here is my attempt:

Example #1

class RevisionControlledValue(models.Model):

    created = models.DateTimeField(auto_now_add=True)
    created_by = models.ForeignKey(User)

    value = models.TextField()

    class Meta:
        ordering = ('-created', )

class DjangoPony(models.Model):

    names = models.ManyToManyField(RevisionControlledValue, \
                related_name="fromname_djangopony_set")
    colors = models.ManyToManyField(RevisionControlledValue, \
                 related_name="fromcolor_djangopony_set")

    @property
    def name(self):
        return self.names.latest('created')

Example #2

class RevisionControlledValue(models.Model):

    created = models.DateTimeField(auto_now_add=True)
    created_by = models.ForeignKey(User)

    content_type = models.ForeignKey(ContentType)
    object_id = models.PositiveIntegerField()
    content_object = generic.GenericForeignKey('content_type', 'object_id')

    value = models.TextField()

    class Meta:
        ordering = ('-created', )

class DjangoPony(models.Model):

    @property
    def name(self):
        return self.revisioncontr开发者_Python百科olledvalue.latest('created')

Both feel a bit iffy to me, especially the content_type one, which I would think should be favorable option.

• With the content_type one, there is no knowledge within the model of the different types of revision controlled fields and what if I want different types of fields?

• For the first one Many to Many does not really match the logic, as it is a One to Many relationship.

Any tips or ideas? :)

There is app for that django-reversion. If you really only want to have reversion control on one field break it off into its own table and make a 1-to-1 relationship.

I think you forgot the word fields in your title. =) I guess I would use an approach that leaves the original model intact. Something starting with:

class DjangoPony(models.Model):
    name = models.TextField()
    color = models.TextField()

class RevisionControlledValue(models.Model):
    created = models.DateTimeField(auto_now_add=True)
    created_by = models.ForeignKey(User)
    value = models.TextField()
    field = models.CharField(max_length=20)

    content_type = models.ForeignKey(ContentType)
    object_id = models.PositiveIntegerField()
    content_object = generic.GenericForeignKey('content_type', 'object_id')

This assumes you'll only be using it for TextFields. To make it really beautiful, you could create a new field, let's say ReversionTextField that automatically creates the reversion object when the model is saved.

@Jason

You don't need to create new models... from the reversion docs:

Saving a subset of fields If you only want a subset of fields to be saved to a revision, you can specify a fields argument to the register method.

reversion.register(YourModel, fields=["pk", "foo", "bar"])

Reversion is pretty well tested and the low level api lets you do pretty much all I've ever wanted.