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An entity type can be marked as transactional. The platform tracks field updates to transactional entities and can rollback changes made to them in the event of an application exception or an explicit rollback. By default entities and collections are transactional while messages are not. A message can be declared transactional which is useful in the event that a message is stored as part of an application's state graph. 

See State Graph Limitations for some important limitations on the current state graph implementation that may have an impact on state modeling.  

Embedded Entities

An entity can be declared as embedded. Embedded entities are serialized as part of the entity/message to which it is declared as a field - as part of the same transported unit. Embedded entities can define fields that are primitive or built in types, other embedded entities, or arrays, but may not use collections or non embedded entities. 

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