This illustration shows an Oracle Streams hub-and-spoke replication environment that includes the following Oracle databases:

• hub.net

• spoke1.net

• spoke2.net

At each database, the local redo log records changes to the hr schema.

The hub.net database has the following Oracle Streams components configured:

• The following queues: source_hns, destination_spoke1, and destination_spoke2.

• A capture process named capture_hns that captures DML changes to the tables in the hr schema from the local redo log. The capture process enqueues these changes into the local source_hns queue.

• A propagation named propagation_spoke1 that sends changes from the local source_hns queue to the destination_spoke1 queue at spoke1.net.

• A propagation named propagation_spoke2 that sends changes from the local source_hns queue to the destination_spoke2 queue at spoke2.net.

• An apply process named apply_spoke1 that dequeues changes that originated at spoke1.net from the destination_spoke1 queue and applies them to the tables in the hr schema.

• An apply process named apply_spoke2 that dequeues changes that originated at spoke2.net from the destination_spoke2 queue and applies them to the tables in the hr schema.

The spoke1.net database has the following Oracle Streams components configured:

• The following queues: source_hns and destination_spoke1.

• A capture process named capture_hns that captures DML changes to the tables in the hr schema from the local redo log. The capture process enqueues these changes into the local source_hns queue.

• A propagation named propagation_spoke1 that sends changes from the local source_hns queue to the destination_spoke1 queue at hub.net.

• An apply process named apply_spoke1 that dequeues changes that originated at hub.net and spoke2.net from the destination_spoke1 queue and applies them to the tables in the hr schema.

The spoke2.net database has the following Oracle Streams components configured:

• The following queues: source_hns and destination_spoke2.

• A capture process named capture_hns that captures DML changes to the tables in the hr schema from the local redo log. The capture process enqueues these changes into the local source_hns queue.

• A propagation named propagation_spoke2 that sends changes from the local source_hns queue to the destination_spoke2 queue at hub.net.

• An apply process named apply_spoke2 that dequeues changes that originated at hub.net and spoke1.net from the destination_spoke2 queue and applies them to the tables in the hr schema.