As you can see, there are many components and methods that can be used to implement replication. Where do you start? What do you use, what don't you use, and when? And most importantly, how does Streams help?

The concept of Streams grew from pairing the distributed theory of Oracle's Advanced Replication with the redo change capture technology of Oracle's LogMiner. Rather than using triggers to capture database changes (as is done with Oracle's Advanced Replication), Streams uses LogMiner to capture the committed changes from the database on-line redo/archive logs. This allows for a more flexible replication architecture (like data capture, propagation, and apply rules that support site-to-site pass-through propagation and data transformations). However, by the nature of redo change capture, Streams replication is always, technically, asynchronous. The data change is committed at the source regardless if it can be committed at the destination. If you require a truly synchronous environment, you will want to explore Oracle Advanced Replication rather than Oracle Streams.