CODEWITHSUNDEEP
pythongoogle-app-engineentity
Chris Dutrow
Chris Dutrow

Reputation: 50362

App Engine - Specify entity name at runtime

In the low-level Java api, I used to be able to make up entity names at runtime.

In python, it seems that I have to pre-define a class name that is also my entity name:

class SomeKindaData(db.Expando):
    pass

sKD = SomeKindaData(key_name='1')
...

Is there a way to make entity names up at run time in App Engine for Python?

Upvotes: 1

Views: 229

Answers (2)

Drew Sears
Drew Sears

Reputation: 12838

Entities themselves don't have names. In the datastore, entities are identified by keys, which can have names or IDs. You're setting your entity's key name to "1" in your sample code. Entities are also classified by kind, in this case SomeKindaData.

db.Model and db.Expando provide a local ORM abstraction around the datastore. When you use these, your entity's kind name is set to your model class name by default. If you don't want to define a model class before creating an entity, you can use the low-level datastore API:

from google.appengine.api import datastore

sKD = datastore.Entity(kind='SomeKindaData', name='1')
sKD['SomeProperty'] = 'SomeValue'
datastore.Put(sKD)

Upvotes: 2

Henry
Henry

Reputation: 6620

I don't know much about App Engine, but you can define classes at run time like this:

def get_my_class(name):
    return type(name, (db.Expando,), {})

So type takes three arguments:

  • name of class
  • tuple of classes to inherit from
  • dictionary of class attributes

Upvotes: 3

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