Oracle Streams 11g Data Replication

CHAPTER 4Capture Process

Oracle Streams replication begins with capturing the changes made to the database objects. There are mainly two ways to capture this information: implicit and explicit.

In the implicit method, the DDL and DML changes are extracted from the redo log buffer, online redo logs, or archived logs. These changes can be captured for the whole database, the entire schema, or a number of tables. As discussed in Chapter 3, the rules determine how the changes are captured at these levels.

In the explicit method, the application creates the messages and enqueues them in the Streams queue. For example, in a heterogeneous environment, changes made to a non-Oracle database are formatted by the user application into LCRs and enqueued ...