title: Entity groups in Google App Engine Datastore
body: <p>So I have an app that if I'm honest doesn't really need transactional integrity (lots of updates, none of them critical).  So I was planning on simply leaving entity groups by the wayside for now.  But I'd still like to understand it (coming from a relational background).</p>
  
  <p>The way I see it, all queries for my app will be on a user by user basis.  Therefore I do not need to group any higher than a user entity, according to the <a href="http://code.google.com/appengine/docs/python/datastore/keysandentitygroups.html#Entity_Groups_Ancestors_and_Paths" rel="noreferrer">docs recommendations</a>.  But I wasn't planning on having a specific user entity, instead relying on UserProperty in the entities themselves.  </p>
  
  <p>The way I see it, if I want transactions (on a per-user basis), I will need some kind of root user entity as the parent of all entities that are part of the hierarchy of her data, no matter how thin this entity would actually be i.e. basically no properties.  </p>
  
  <p>Is this correct?</p>
  
  <p>Apologies for verboseness, I only really pinged what schema-less actually meant in practice tonight...</p>