问题
I have a below use case:
I have a method that accepts a list of strings. For each of the strings, I need to create a property under an existing google data store entity A
Example: I have an existing entity Person with properties fname and lname.
If the input list has strings - address, city, I need to update the entity Person to include these new properties address and city.
I'm coding this use case in Python. Any suggestions on how I can achieve this?
回答1:
So the best way to do this is to let your class inherit ndb.Expando. The difference between Expando and Model is that you can always add attributes to an Expando entity and be able to store it in the Datastore.
Knowing this, there are several ways to proceed, but I am guessing you’re also going to need to use Python’s setattr(object, name, value) method to pass the attribute name from a string.
回答2:
Take a look at the Expando model class: https://cloud.google.com/appengine/docs/standard/python/ndb/creating-entity-models#creating_an_expando_model_class
class Person(ndb.Expando):
pass
person = Person(fname='some', lname='body')
person_key = person.put()
...
person = person_key.get()
person.city = 'San Francisco'
person.address = '1234 Main St.'
person.put()
来源：https://stackoverflow.com/questions/45570769/add-properties-to-google-datastore-entity-dynamically