Unique Constraint At Data Level in GAE

Question

It seems that the unique constraint is not natively supported in GAE, although one can enforce unique check before putting an object to store.

But tha

Answer 1

No, you still cannot specify unique during schema creation.

This issue is located here in case you want to watch it. It doesn't show up on their list of features on deck yet, so it seems like there are other features they will be working on first.