How to implement dependencies on data entry in Django?

Question

Django

Welcome all. Stuck on the next task and can not figure out how to do it. If there is an example I would be grateful.
The essence of the problem:
When adding a new product (model1), depending on the category, a form with attributes should be opened (model2 different for each category). When saving, the selected attributes must be saved as a list in the model field1 based on the selected values ​​in the attribute form.

Answer 1

Look towards ForeignKeys.

Answer 2

If you want to bind events to create and change models, look towards signals
djbook.ru/rel1.7/topics/signals.html