CODEWITHSUNDEEP
google-app-enginegoogle-cloud-datastorejdo
Lumpy
Lumpy

Reputation: 3652

GAE: Child object that is not in the class

I am trying to duplicate the pattern described in Building Scalable, Complex Apps on App Engine. I am having trouble understanding how to tell GAE that Message index is a child of Message. From google, they say that you create a child object by including it in the parent class, but this is exactly what we are trying to prevent. So how do I store an entity as a child without including it in the parent class.

Upvotes: 3

Views: 129

Answers (1)

Robert Kluin
Robert Kluin

Reputation: 8292

In the context of entity groups, 'child' means the MessageIndex's key is a descendant of the Message's key. It does not mean the MessageIndex list (or collection) is a property of the Message.

See the section titled "Creating Entities With Entity Groups" in documentation on transactions for an example of how to do this in Java. http://code.google.com/appengine/docs/java/datastore/transactions.html

Upvotes: 1

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