Partial update and cross-field validation

[Juan Antonio Alvarez]

Hi there!

I'm working on an application that needs to do lots of cross checking. We also support partial updates, son on every save I usually end up doing something like:

if 'validate_field' in self.validated_data:

  validation_value = self.validated_data['validate_field']

else:

  validation_value = self.instance.validate_field

# .. Validation logic here

I keep asking myself:

* Is this a valid approach? As in, will it bite me later?

* Is there a better way to do it?

Thank you,

Juan

[Tom Christie]

That seems perfectly reasonable to me, yup, although you might want to use the following pattern:

    field_value = self.validated_data.get('validate_field', self.instance.validated_field)

[Juan Antonio Alvarez]

That seems perfectly reasonable to me, yup, although you might want to use the following pattern:

    field_value = self.validated_data.get('validate_field', self.instance.validated_field)

More pythonic indeed. Thank you!