A homogenous distributed database system is a network of two or more Oracle databases that reside on one or more machines.
Figure 3-6 illustrates a distributed system that connects three databases: hq, mfg, and sales.
An application can simultaneously access or modify the data in several databases in a single distributed environment. For example, a single query from a Manufacturing client on local database mfg can retrieve joined data from the products table on the local database and the dept table on the remote hq database. For a client application, the location and platform of the databases are transparent.
You can also create synonyms for remote objects in the distributed system so that users can access them with the same syntax as local objects. For example, if you are connected to database mfg but want to access data on database hq, creating a synonym on mfg for the remote dept table enables you to issue this query:
SELECT * FROM dept;
In this way, a distributed system gives the appearance of native data access. Users on mfg do not have to know that the data they access resides on remote databases.