Question

I want to define a setter function for a Django model field in order to validate the input and immediately raise a error if value is not valid.

I don’t think that doing the validation in save() or pre_save() is a feasible solution for my problem because of things beyond my control.

Also changing the field into a property and use plain field.getter and field.setter are not feasible as this will break .filter(), .exclude() etc on the field, plus it will require a scheme change even if I changed field to _field and overrode the manager.

So, am I forced to override __setattr__ or is there a better way of doing this?

Answer 1

See this django ticket:

https://code.djangoproject.com/ticket/3148

Also, see here for discussion:

Django model fields getter / setter

And this blog post:

http://www.b-list.org/weblog/2006/aug/18/django-tips-using-properties-models-and-managers/

Also note there is the option of using a custom manager that translates your filter kwargs for you, and using _name for fields, and making your own @name.setter @name.getter etc.