How to create dynamic fields in Google App Engine

问题:

I have a db expando class called widget.

I'm passing in a json string and converting it to a dict and then adding it to the datastore.

My question is how can I loop through my dict to create dynamic fields.

widget = Widget.get_by_key_name(key_name)
widget.name = self.request.get('wname')
fields = simplejson.loads(self.request.get('wcontents'))
for k,v in fields.iteritems():
  widget.k = v

This renders "k" as my field name as oppose to the k value in the dict.

回答1:

The syntax widget.k references the attribute k on object widget. To dynamically choose which attribute you set, use the built-in setattr method:

setattr(widget, k, v)

Dynamically setting an attribute like this will create the field on that particular entity.

回答2:

Try:

for k, v in fields.items()