8. A system comprising one or more computers and one or more storage devices storing instructions that, when executed by the one or more computers, cause the one or more computers to perform operations comprising: receiving a transaction representing an update to a master graph database, the transaction including a new primitive and a first unique identifier for the new primitive in the master graph database; updating a concentric graph database with the new primitive, wherein the concentric graph database includes a first plurality of primitives and a second plurality of primitives, wherein each of the first plurality of primitives is also included in the master graph database and none of the second plurality of primitives are included in the master graph database, and wherein updating the concentric graph database with the new primitive comprises assigning a different, second unique identifier to the new primitive in the concentric graph database; and storing a mapping from the second unique identifier to the first unique identifier in the concentric graph database.
14. The system of claim 8 , the operations further comprising: storing the mapping as a link primitive in the concentric graph database, wherein the link primitive includes the first unique identifier, the second unique identifier, and data indicating that the link primitive defines an identifier for the new primitive in the concentric database that is equivalent to the second identifier for the new primitive.