Here are some architectural information on dealing with disparate entity types with Windows Azure Table Storage.
For example you have an objective to store some kind of application entitlement information in Windows Azure table storage and to handle the information effectively, you have the following pair of entity distribution:
When you are going to add or update an entitlement, you can consider the following:
To handle above situation here are some expert tips:
As you may know upsert is not available yet with Windows Azure Storage API however keep an eye at Windows Azure Storage Team announcement and you may see some update on this regard.
More info: Working with Azure Tables with Multiple Entity Schemas by Jeffrey Richter