Multiple Copies Distributed over a Network

When copies of tables are distributed over a WAN in a decision-support application, all updates are performed by applications executing at the primary site and are distributed to the remote sites that have subscriptions for the data.

Multiple LAN Decision-Support Replicate

Figure 2-2 illustrates that when copies of tables are distributed over a wan in a decision-support application, all updates are performed by applications executing at the primary site and are distributed to the remote sites that have subscriptions for the data. No remote updates take place. There is a Replication Server in the primary and replicate sites to facilitate replication between the two sites.

This type of system uses the centralized primary maintenance method of updating primary data. Clients at remote sites subscribe to replication definitions or publications of primary data. They do not update primary data.