django rest framework viewset perform_update

The perform_update method in Django's REST framework's ViewSet class is responsible for handling the update operation on a single object.

Here is an explanation of each step in the perform_update method:

1. First, the method retrieves the existing object that needs to be updated from the database. This is done by calling the get_object method, which retrieves the object based on the provided lookup parameters.

2. Then, the method deserializes the updated data from the request's body. This is done using the get_serializer method, which returns an instance of the serializer associated with the viewset. The serializer is responsible for validating and transforming the incoming data.

3. Next, the method calls the partial_update method on the serializer instance, passing the existing object and the deserialized data. The partial_update method performs the actual update on the object, applying only the fields that were included in the request.

4. After the update is performed, the method checks if the serializer has a save method. If it does, the method calls the save method on the serializer to persist the changes in the database.

5. Finally, the method returns the updated object as the response.

It's important to note that the perform_update method can be overridden in your viewset subclass to customize the update behavior according to your requirements.