Consolidation model
In the consolidation model, data changes are made at the remote sites and then propagated to the central database. The central database is read-only and is used for reporting purposes. For replication, this model increases the frequency of data collision over the distribution model. If there is a collision of changes by two or more users, the changes are applied on a first-come-first-served basis.
To avoid data collision, the consolidation model often uses table partitioning. Table partitioning (also called data ownership) requires that all data be owned by each site. Changes to data at each remote site are made exclusively by respective remote site users. A data ownership model might not be appropriate for your business organization. Although data collisions are avoided, the ability to update the same record from any site is lost.
Figure 10–2 illustrates two data consolidation models, one with no data ownership, and the other with table partitioning.
Peer-to-peer model
In a peer-to-peer model (or “update anywhere”) any user at any site can update data. This is the most flexible replication model. However, in a peer-to-peer scheme, data collision is a side effect that must be addressed. Data collision must be resolved based on business requirements.
Figure 10–3 illustrates the peer-to-peer model.
