如何从Google App Engine NDB更新查询？

Question

We are using Google App Engine in Python. I have code that saves a new object to the database, and then queries the database to receive all the objects. The problem is that the query returns all the objects except the new object I created. Only after refreshing the page I see the new object. Is there a way to update the query to include all the objects, including the new object I created? Here is my code:

if (self.request.get("add_a_new_feature") == "true"):
    features = Feature.gql("WHERE feature_name=:1 ORDER BY last_modified DESC LIMIT 1", NEW_FEATURE_NAME) # class Feature inherits from ndb.Model
    if (features.count() == 0):
        new_feature = Feature(feature_name=NEW_FEATURE_NAME)
        new_feature.put()
...
features = Feature.gql("ORDER BY date_created")
if (features.count() > 0):
    features_list = features.fetch()
    for feature in features_list:
        ... # the list doesn't contain new_feature

Answer 1

As mentioned in the comments - this is an expected behaviour. Take a look at this article for additional information. As a quick fix/hack you could simply get the data from datastore before adding the new entity and then append it to the list.

features = Feature.gql("ORDER BY date_created")

if (self.request.get("add_a_new_feature") == "true"):
    if (Feature.gql("WHERE feature_name=:1 ORDER BY last_modified DESC LIMIT 1", NEW_FEATURE_NAME).count() == 0):
        new_feature = Feature(feature_name=NEW_FEATURE_NAME)
        new_feature.put()
        features.append(new_feature)
...

if (features.count() > 0):
    features_list = features.fetch()
    for feature in features_list:
        ... # the list now contain the new_feature at the end

Depending on what Entity.gql() returns when there are no results (None or [ ]?) you may need to check whether features is a list before appending. You could also probably avoid the second query since you already have a list of features and could loop through it in Python rather than sending another request to datastore.