Showing posts from 2014

Flashback Data Archive - New Feature Oracle Database 11g

Set Up and Use a Flashback Data Archive Retaining a historical record of all changes to rows in critical tables is error prone and requires custom applications or database triggers to maintain repositories for the historical changes. Every time you create a new application or update a table in an application that requires historical tracking, you must make changes to your tracking application as well. You can use Flashback Data Archive to save historical changes automatically to all key tables for as long as possible.

Understanding Flashback Data Archive In Flashback Data Archive you create one or more repository areas (dedicated tablespace) (one of which can be the default), assign a default retention period for objects in the repository, and then mark the appropriate tables for tracking.
A Flashback Data Archive acts much like an undo tablespace. However, a Flashback Data Archive records only UPDATE and DELETE statements but not INSERT statements. In addition, undo data is typically…

Oracle Architecture - Explained In Detailed - Administration I

Figures shown in these notes are from Oracle® Database Concepts 11g Release 2

These notes introduce the Oracle server architecture.The architecture includes physical components, memory components, processes, and logical structures.

Primary Architecture Components

The figure shown above details the Oracle architecture.
Oracle server:An Oracle server includes an Oracle Instance and an Oracle database. ·An Oracle database includes several different types of files:datafiles, control files, redo log files and archive redo log files.The Oracle server also accesses parameter files and password files. ·This set of files has several purposes. oOne is to enable system users to process SQL statements. oAnother is to improve system performance. oStill another is to ensure the database can be recovered if there is a software/hardware failure. ·The database server must manage large amounts of data in a multi-user environment. ·The server must manage concurrent access to the same data. ·The server mu…