Geodatabase replication allows you to create copies of data across two or more geodatabases so changes to the data can be synchronized.
Replica creation involves the user defining the data to replicate from a source geodatabase and then running a process to create replicas. The process copies data from the source geodatabase to a target geodatabase and creates a replica in each geodatabase. The replica describes what data has been replicated and contains the information needed to synchronize changes. The replica in the source geodatabase is the parent replica, and the replica in the target geodatabase is the child replica. Each combination of child and parent replicas is a replica pair. The term relative replica refers to the other replica in a replica pair.
The source must be an enterprise geodatabase, and therefore, parent replicas can only be hosted by enterprise geodatabases. You can also create multiple replicas from a single-source geodatabase. For example, you can create a replica for each county from your statewide enterprise geodatabase. The data involved in each replica can also overlap. The diagram below shows multiple replicas created from a single-source geodatabase.
An enterprise geodatabase can host both child and parent replicas. This enables data to be replicated across multiple geodatabases. The diagram below displays an example where three enterprise geodatabases have replication configured between them. DatasetA originates from the enterprise geodatabase on the left. A two-way replica was then created for datasetA using the center enterprise geodatabase as the destination to host the child replica. A second two-way replica was then created for datasetA using the center enterprise geodatabase as the source and the enterprise geodatabase on the right as the destination to host the child replica.
With these replicas in place, a change made to datasetA in the right-hand geodatabase can be applied to the center geodatabase, which can then apply the change to the origin geodatabase on the left. Since two-way replication is used, changes made in any geodatabase can be replicated to any other geodatabase in the same way.
It is also possible for a single enterprise geodatabase to host multiple child replicas. In this case, however, the datasets involved in each child replica must be distinct. For example, if a feature class named Parcels is involved in one child replica, it cannot participate in any other child replicas in the same geodatabase. The diagram below shows a single enterprise geodatabase hosting multiple child replicas, each referencing distinct datasets.
A file geodatabase can be used as the target for a checkout/check-in or one-way replica. File geodatabases can also only host a single checkout/check-in or one-way replica at a time.