Question

This will not work, but will illustrate my question:

query = "my_model".all()
print query.count()

Answer 1

I have found a solution, by diving into the datastore code.

from google.appengine.ext import db

model_class = db.class_for_kind("my_model")     # this method is not published
query = model_class.all()
print query.count()

db_class_for_kind can only work if the model is already imported. But you can import the model_class :

__import__("my_model_path", globals(), locals(), ["my_model"]], -1)

db.class_for_kind is not published. See also this feature request: http://code.google.com/p/googleappengine/issues/detail?id=800