Oracle Essentials Oracle Database 11g (8 page)

Many of these partitioning types can be used in combination as “composite” partitions. Examples of composite partitions in Oracle Database 11
g
include range-range, range-hash, range-list, list-range, list-hash, and list-list.

Data Guard

Oracle first introduced a standby database feature in Oracle 7.3. The standby database provides a copy of the production database to be used if the primary database is lost—for example, in the event of primary site failure or during routine maintenance. Primary and standby databases may be geographically separated. The standby database is created from a copy of the production database and updated through the application of archived redo logs generated by the production database. Data Guard,
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first introduced in Oracle9
i
, fully automates this process; previously, you had to manually copy and apply the logs. Agents are deployed on both the production and standby database, and a Data Guard Broker coordinates commands. A single Data Guard command invokes the eight steps required for failover.

In addition to providing physical standby database support, Data Guard can create a logical standby database. In this scenario, Oracle archive logs are transformed into SQL transactions and applied to an open standby database.

Oracle Database 10
g
introduced several new features, including support for real-time application of redo data, integration with the Flashback database feature, and archivelog compression. Starting with Oracle Database 10
g
, rolling upgrades are supported. As of Oracle Database 11
g
, the Active Data Guard Opton enables the standby database to be used for queries, sorting, and reporting even as changes from the production system are being applied.

Fail Safe

The Fail Safe feature provides a higher level of reliability for an Oracle database.

Failover is implemented through a second system or node that provides access to data residing on a shared disk when the first system or node fails. Oracle Fail Safe for Windows, in combination with Microsoft Cluster Services, provides a failover solution in the event of a system failure.

Fail Safe is primarily a disaster recovery tool, so some downtime does occur as part of a failover operation. The recommended solution for server availability, since Oracle9
i
, is Real Application Clusters.

Oracle Real Application Clusters

Real Application Clusters (RAC) replaced the Oracle Parallel Server (OPS) option beginning with Oracle9
i
. RAC can provide failover support as well as increased scalability on Unix, Linux, and Windows clusters. Key to improved scalability was the introduction of Cache Fusion that greatly minimizes the amount of writing to disk that was formerly used to control data locks. Oracle Database 10
g
introduced a new level of RAC portability and Oracle support by providing integrated “clusterware” for the supported RAC platforms.

With Real Application Clusters, you can deploy multiple Oracle instances on multiple nodes of a clustered solution or in a grid configuration. RAC coordinates traffic among the systems or nodes, allowing the instances to function as a single database.

As a result, the database has proven to scale across dozens of nodes. Since the cluster provides a means by which multiple instances can access the same data, the failure of a single instance will not cause extensive delays while the system recovers. You can simply redirect users to another instance that’s still operating. Applications can leverage the Oracle Call Interface (OCI) to provide failover to a second instance transparently to the user.

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Chapter 1: Introducing Oracle

Data Guard and RAC

Data Guard and RAC in combination replaced Parallel Fail Safe beginning with Oracle9
i
. Data Guard provides automated failover with bounded recovery time in conjunction with Oracle Real Application Clusters. In addition, it provides client rerouting from the failed instance to the instance that is available with fast reconnect and automatically captures diagnostic data.

Automated Storage Management

Oracle Database 10
g
introduced Automated Storage Management (ASM), which provides optimum striping and mirroring of data for performance and availability.

Because ASM is managed through Enterprise Manager, the database administrator now can perform this critical management task. The need to coordinate this activity with a system administrator is thus greatly reduced.

Real Application Testing Option

Oracle Database 11
g
introduced the capability to rerun production workloads and test system changes through the Real Application Testing Option. This database option includes a Database Replay facility and the SQL Performance Analyzer. Database Replay captures production workload information, including concurrency, dependencies, and timing. It transforms the workload capture files into replay files, provides a Replay Client for processing the replay files, and provides the means to report on performance statistics and any errors that might occur. The SQL Performance Analyzer captures a SQL workload to be analyzed, measures the performance before database changes and afterward, and identifies performance changes among SQL statements.

Database Security Features

Oracle includes basic security for managing user access through roles and privileges.

These can be managed through Enterprise Manager on a local basis or on a global basis by leveraging Oracle’s enterprise user security, a feature in the Advanced Secu-

rity Option. We describe Oracle’s database security features in Chapter 6.

Database security features allow you to implement a Virtual Private Database (VPD) using Oracle by creating and attaching policies to database tables, views, or synonyms. These policies are then enforced by placing a predicate WHERE clause on SELECT, INSERT, UPDATE, DELETE, and/or INDEX statements.

Many organizations face the need to meet more stringent compliance requirements for improved data protection, although database usage now can extend beyond organizational boundaries. Oracle has added several options to the database to enable secure deployment in such challenging environments. These options include the Advanced Security Option, Label Security Option, Database Vault, and Audit Vault.

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Advanced Security Option

The Advanced Security Option was once known as the Advanced Networking Option (ANO). Key features for enabling a more secure Oracle Net include use of encryption services such as RSA Data Security’s RC4, the U.S. Data Encryption Stanadard (DES), Triple DES, and the Advanced Encryption Standard (AES).

Authentication can be through Kerberos, RADIUS, or the Distributed Computing Environment (DCE). Network data integrity checking uses MD5 or SHA-1. Oracle Database 11
g
added enhanced transparent data encryption and expanded Kerberos authentication leveraging of Oracle’s encryption types.

Label Security Option

Oracle Label Security controls access to data by comparing labels assigned to rows of data with label authorizations granted to users through their privileges. Multiple authorization levels are possible within a single database. Label security authorizations are managed through a Policy Manager. Policies are enforced in the database instead of through views, thus greatly simplifying management of data accessibility and providing a more secure implementation.

Database Vault Option

Oracle Database Vault Option provides fine-grained access control to data for everyone with access to the database, including database administrators. The security administrator can set factors to define access to the database and audit specific dimensions of security. At a more granular level, realms can be defined for limiting access to specific schemas and roles.

Audit Vault Server

Oracle Audit Vault Server monitors database audit tables, redo logs, and operating system audit files for suspicious activities. It can then generate reports or send alerts showing where such unusual activity is occurring.

Oracle Development Tools

Many Oracle tools are available to developers to help them present data and build more sophisticated Oracle database applications. Although this book focuses on the Oracle database, this section briefly describes the main Oracle tools for application development: Oracle JDeveloper, Oracle SQL Developer, and Oracle Developer Suite. The Developer Suite, sometimes referred to as the Oracle Internet Developer Suite, consists of Oracle Forms Developer, Oracle Reports Developer, Oracle Designer, Oracle Discoverer Administrative Edition, and Oracle Portal.

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Chapter 1: Introducing Oracle

Oracle JDeveloper

Oracle JDeveloper was introduced by Oracle in 1998 to enable the development of basic Java applications without the need to write code. JDeveloper is now available for free and can be downloaded from the Oracle Technology Network. It includes a Data Form wizard, a Beans Express wizard for creating JavaBeans and BeanInfo classes, and a Deployment wizard. JDeveloper includes database development features such as various Oracle drivers, a Connection Editor to hide the JDBC API complexity, database components to bind visual controls, and a SQLJ precompiler for embedding SQL in Java code that youcan then use with Oracle. Youcan also deploy applications developed using JDeveloper to Oracle’s Application Server.

Although JDeveloper uses wizards to allow programmers to create Java objects without writing code, the end result is generated Java code.

Oracle SQL Developer

Oracle SQL Developer was introduced in 2006 and can be used to connect to any Oracle database dating back to Oracle9
i
Release 2. SQL Developer can create connections to Oracle databases, browse database objects, create and modify database objects, query and update data, export data and DDL, import data, process commands, and run and create reports. The product’s tools support the editing, debugging, and running of PL/SQL scripts. In addition, SQL Developer can be pointed at non-Oracle databases to view their database objects and data, and it provides capabilities to begin a migration to an Oracle database.

SQL Developer is available at no charge and can be downloaded from the Oracle Technology Network. Versions are available for Windows, Linux, and Apple Mac OS X. Oracle also hosts a SQL Developer forum at the Oracle Technology Network site.

Oracle Forms Developer

Oracle Forms Developer is a tool for building forms-based applications and charts for deployment as traditional client/server applications or as three-tier browser-based applications via Oracle Application Server. Developer is a fourth-generation language (4GL). With a 4GL, you define applications by defining values for properties, rather than by writing procedural code. Developer supports a wide variety of clients, including traditional client/server and Java-based clients. The Forms Builder includes a built-in JVM for previewing web applications.

Oracle Reports Developer

Oracle Reports Developer provides a development and deployment environment for rapidly building and publishing web-based reports via Reports for Oracle Application
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Server. Data can be formatted in tables, matrices, group reports, graphs, and combinations. High-quality presentation is possible using the HTML extension Cascading Style Sheets (CSS).

Oracle Designer

Oracle Designer provides a graphical interface for Rapid Application Development (RAD) for the entire database development process—from building the business model to schema design, generation, and deployment. Designs and changes are stored in a multiuser repository. The tool can reverse-engineer existing tables and database schemas for reuse and redesign from Oracle and non-Oracle relational databases.

Designer also includes generators for creating applications for Oracle Developer, HTML clients using Oracle Application Server, and C++. Designer can generate applications and reverse-engineer existing applications or applications that have been modified by developers. This capability enables a process called
round-trip engineering
, in which a developer uses Designer to generate an application, modifies the generated application, and reverse-engineers the changes back into the Designer repository.

Oracle Discoverer Administration Edition

Oracle Discoverer Administration Edition enables administrators to set up and maintain the Discoverer End User Layer (EUL) for Oracle’s previous generation of business intelligence tools. The purpose of this layer is to shield business analysts using Discoverer as an ad hoc query and analysis tool from SQL complexity. Wizards guide the administrator through the process of building the EUL. In addition, administrators can place limits on resources available to analysts monitored by the Discoverer query governor.

Oracle Portal

Oracle Portal, introduced as WebDB in 1999, provides an HTML-based tool for developing web-enabled applications and content-driven web sites. Portal application systems are developed and deployed in a simple browser environment. Portal includes wizards for developing application components incorporating “servlets” and access to other HTTP web sites. Portals can be designed to be user-customizable and are deployed to the middle-tier Oracle Application Server.

Oracle Portal brought a key enhancement to WebDB, the ability to create and use
portlets
, which allow a single web page to be divided up into different areas that can independently display information and interact with the user. For example, Oracle Answers, Discoverer, and Reports can be accessed as portlets.

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Chapter 1: Introducing Oracle

Oracle’s next generation portal framework product, introduced in 2006, and initially made available as an Application Server option is WebCenter.