This illustration shows two master sites named
pa.example.com maintaining a replication group. There is a two way arrow between the master sites indicating that a database link exists at each site which connects to the other master site.
The materialized view sites
kc.example.com each maintain a replication group with the master site
or.example.com. A materialized view site
ph.example.com maintains a replication group with the master site pa.example.com. A one way arrow points from each materialized view site to its master site, indicated a database link from the materialized view site to the master site.