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Wednesday, February 25, 2009

What is Oracle Stream?



What is Oracle Stream?

Oracle Streams enables information sharing. Using Oracle Streams, each unit of shared information is called a message, and you can share these messages in a stream. The stream can propagate information within a database or from one database to another. The stream routes specified information to specified destinations. The result is a feature that provides greater functionality and flexibility than traditional solutions for capturing and managing messages, and sharing the messages with other databases and applications. Streams provides the capabilities needed to build and operate distributed enterprises and applications, data warehouses, and high availability solutions. You can use all of the capabilities of Oracle Streams at the same time. If your needs change, then you can implement a new capability of Streams without sacrificing existing capabilities.

Streams Information Flow



What Can Streams Do?

The following sections provide an overview of what Streams can do.

· Capture Messages at a Database

· Stage Messages in a Queue

· Propagate Messages from One Queue to Another

· Consume Messages

· Other Capabilities of Streams

A capture process can capture database events, such as changes made to tables, schemas, or an entire database. Such changes are recorded in the redo log for a database, and a capture process captures changes from the redo log and formats each captured change into a message called a logical change record (LCR). The rules used by a capture process determine which changes it captures, and these captured changes are called captured messages.

Etc…

What Are the Uses of Streams?

The following sections briefly describe some of the reasons for using Streams. In some cases, Streams components provide infrastructure for various features of Oracle.
• Message Queuing
• Data Replication
• Event Management and Notification
• Data Warehouse Loading
• Data Protection
• Database Availability During Upgrade and Maintenance Operations