google app engine datastore
Assuming that you are talking about an entity that you have on your local machine but not on App Engine once you deploy the app: your local datastore is for testing purposes only and nothing from it will be deployed to GAE. You will need to re-create all datastore data once your app is deployed if it wasn't there already.
I have an instance which is blobstore.BlobReferenceProperty() in local data base viewer it appears but when I deploy the application in the google database the value is '{}' and when click on an entity it appears at that instance that it has an unknow property.Can anyone help me?