When someone says, "I work with Oracle" what does he or she mean? The name Oracle (not to be confused with ORACLE, an early computer built by the Oak Ridge National Laboratory) can be used to refer to several different aspects of Oracle Corporation and its products. Oracle is a company, a database, and a family of products.
Oracle Corporation as we know it, began in 1977 as a company called Software Development Laboratories (SDL), founded by Larry Ellison, Bob Miner, and Ed Oates. These men, inspired by the relational theory set forth by Dr. Ted Codd and the work done on an IBM project known as System R, set out to develop the relational idea into a commercial product. In 1979, the company, renamed Relational Software Inc. (RSI), sold the first version of their relational database software, called Oracle, to Wright-Patterson Air Force Base. Although it was the first version of the Oracle database, it was designated as Version 2 because Larry Ellison didn't believe that customers would buy a Version 1 product. In 1982, RSI was renamed Oracle Corporation to more closely align the company with its flagship database.
For many years, the Oracle database software was primarily available on mainframe and minicomputer systems, the primary computing platforms of that time. In 1983, in a move that would bode well for Oracle's future, Version 3 was rewritten in the C programming language, making it portable to many other platforms. It was ported to the PC architecture with Version 4. The modern history of Oracle Corporation can be traced to the release of Oracle Version 7 in 1992. Version 7 released many new enhancements, including new security and performance features. It is at this point that the Oracle database software began its rise to become the most widely used commercial RDBMS in the world.
Since Oracle's inception, the Oracle Database Server has been and remains Oracle's flagship product. It has maintained its position as the world's most widely used database for many years and stands essentially unchallenged in the market today. The Oracle database is designed to be high performing, highly available, and highly secure. It can run on a variety of hardware and operating system platforms. One of the Oracle Database Server's strengths is its ability to run on a range of system types, from small departmental servers to massive symmetric multiprocessing servers to enormous highly available clustered systems. Many of the largest companies in the world run their database systems on Oracle software. Oracle currently holds a larger revenue share of the worldwide RDBMS market than its five closest competitors combined.
The primary language used to access Oracle databases is Structured Query Language , (SQL). SQL (pronounced either "S-Q-L" or "sequel") is the language most commonly used to address relational databases today, and likely will be for some time to come. The structure and syntax of SQL are governed by the American National Standards Institute (ANSI) and the International Organization for Standardization (ISO). It is these organizations that decide, albeit with input from other companies such as Oracle, what comprises the accepted standard for SQL. The current revision is SQL 2008. Although most commercial RDBMS products generally conform to the ANSI standard, they can differ in their implementations. This means that not every RDBMS uses the exact same SQL syntax. Oracle database also supports the use of two other programming languages within the database: PL/SQL and Java. PL/SQL is Oracle's proprietary third-generation programming language. It allows programmers to write structured code that integrates easily with SQL and stores that code as objects within the database. Java is an industry standard object-oriented language used in many types of applications today. Oracle also supports the storage of Java code within the database.
Apart from the different versions of Oracle available, Oracle also offers a number of different editions of their database software. These editions primarily differ by cost and availability of features. They are as follows:
Enterprise Edition (EE):The EE has no maximum as to the number of server central processing unit (CPU) sockets allowed, as well as no limits on memory accessibility or database size. It contains a number of database options not found in any of the other editions. It is available for Linux, Unix, and Windows, and supports both 32-bit and 64-bit versions.
Standard Edition (SE): The SE is only available for servers with four or fewer CPU sockets, although, like the EE, it has no limits on memory or database size. It includes many database options, though generally fewer than the EE. It is also available for Linux, Unix, and Windows, and supports both 32-bit and 64-bit versions. The SE and the SE1 can also be licensed on a per user basis, rather than the standard per CPU core basis.
Standard Edition (SE1): The SE1, although similar in many respects to the SE, only supports servers with two or fewer CPU sockets. SE1 is available for Linux, Unix, and Windows. For smaller IT organizations that don't require large database servers, SE1 can provide a low-cost, high-performance database solution.
Express Edition (XE): The XE is a somewhat different product, an entry-level, free version of the Oracle database that lacks many of the capabilities of higher editions. It can only support one CPU and has a 1 GB limit for usable random access memory (RAM) and a maximum database size of 4 GB. It is only available for Linux and Windows, and lacks the 64-bit support. The XE is primarily targeted for developers working on applications that will eventually be deployed in larger environments.
Oracle also offers Oracle Personal Edition (PE), a low-cost, full-featured version of the Oracle database. PE is restricted to only one user per database, but provides access to all the features of the EE. Throughout the course of the book, we will use and focus on the Enterprise Edition so as to have access to the widest range of features.
Note
The real-world DBA
Although the Enterprise Edition of Oracle is the most commonly found one in the IT world, a DBA shouldn't completely discount other editions. Often, significant cost savings can be achieved for companies that don't require "all the bells and whistles." Also, although uncommon, Oracle may separately negotiate the licensing of the EE at a lower cost, provided that the license being purchased is large enough. In these situations, companies may negotiate the purchase of the EE without a license for some of the included options. This can result in a DBA being required to administer an EE database that lacks the expected features. Always check your licensing agreement.
In addition to the various editions of the Oracle RDBMS, Oracle offers a number of options, depending on your chosen edition. These options function primarily as "add-ons," and are available at an additional cost. Some of the more commonly used options are listed here:
Advanced Security : This is an option, sometimes known as ASO for Advanced Security Option, that provides encryption for both data at rest and data in transit over a network. It can also integrate with services such as Kerberos and RADIUS to provide strong authentication.
Active Data Guard : This is an enhancement to the standard Data Guard feature that provides the ability to create a standby copy of the database that can also be used for read-only business reporting.
Advanced Compression : This allows the use of internal compression routines within the database that facilitate reduction of disk use. It is especially useful in databases that store large amounts of binary data.
Total Recall : This is an add-on that simplifies the long-term storage of large amounts of historical data. This can be important for environments that are subject to compliance and accounting audits, such as the health insurance and legal industries.
Partitioning : This is a feature that allows a DBA to take a very large table, with perhaps many millions of rows, and convert it into a partitioned table. A partitioned table is one that actually exists as a number of smaller tables that can be seen as one. Under certain circumstances, this can dramatically improve the performance of queries, particularly in data warehousing environments.
Database Vault : This is an option that extends Oracle's auditing capabilities and allows for extremely fine-grained access control over the database environment.
Real Application Clusters : This is a popular enhancement, usually referred to as RAC, which allows database servers to be clustered together and appear as one large database. RAC can be an essential component for a high-availability database environment.
Although the Oracle Database Server is the cornerstone of their product offerings, Oracle has offered additional types of software products for many years. Recently, however, Oracle has acquired an enormous number of software companies to add to their product family. In 2009, Oracle acquired Sun Microsystems, signaling an important shift in the direction of the company. With the acquisition, Oracle acquired Sun's well-respected line of hardware, as well as the Solaris operating system, the MySQL open source RDBMS, and the Java programming language. Although many in the industry believed that this move would signal the end of Sun's software product line, Oracle has continued to offer, promote, and support many of these products. As a result, Oracle now offers a staggering amount of hardware and software solutions that span every layer of enterprise IT, including hardware, operating systems, databases, application servers, and enterprise administration. An exhaustive discussion of the complete line of Oracle products is beyond the scope of this book; however, we mention some of the most important ones here.
With the purchase of Sun Microsystems, Oracle achieved its long standing desire to offer complete hardware solutions bundled with Oracle software. These hardware products come pre-installed with Oracle software and are ready to operate after a quick installation and configuration. They represent an attractive offering for customers that require new solutions that can be up and running in a short period of time. The flagship of Oracle's product line is the Exadata Database Machine . Exadata is a complete hardware/storage/database solution that provides a highly available, high performance database platform out of the box. Exadata can provide superior performance for most types of database operations, since the hardware itself is tailored to the requirements of the database. Oracle also offers the Database Appliance , a smaller, less expensive platform tailored for the Oracle Database that lacks some of the high-performance features of Exadata. For the application server side of IT, Oracle offers Exalogic and Exalytics , two hardware platforms that can be used to support application operations and data analysis, respectively.
Server virtualization has become extremely important to enterprise IT in recent years. The concept of allowing one server or a group of servers to appear as many virtual servers provides IT organizations with a way to make more effective use of expensive hardware resources. Say for instance that a company's database servers, on average, use less than 50 percent of their available memory, and run at 20 percent CPU usage. With virtualization, these servers could serve as hosts for virtualized servers and make more effective use of these resources. When users connect to these virtual servers, they see what appears to be a physical machine, when in reality they are connected to a virtual machine. For enterprises, Oracle offers Oracle VM , a complete virtualization solution that allows servers to host virtual machines. Oracle VM is based on the Xen Hypervisor technology and actually runs from a Linux kernel. For desktop-level virtualization, Oracle offers VirtualBox , which it acquired from Sun. With VirtualBox, users can create their own virtual machines on a desktop system, such as a personal computer. To do this, we simply install the VirtualBox software on a PC and create a new virtual machine. Then we install the operating system, as well as any other software we desire, on this empty virtual machine.
Note
The real-world DBA
It is interesting to note that the author runs VirtualBox on a Linux desktop and can use it to run many different operating systems, including DOS, Windows 95, and several distributions of Linux. In fact, all of the screenshots in this book were taken using Oracle databases and tools running in virtual machines from a desktop. VirtualBox can be a great way to experience and learn about different operating systems without trying to maintain multiple computers at home!
The choice of an operating system for any platform running the Oracle database is a crucial one. The operating system stands between the database and the hardware that services the needs of the database. An operating system that makes efficient use of hardware resources to serve the database can have a positive impact on the performance of the database. Although many Oracle products are supported on various operating systems, Oracle offers two different operating systems of their own.
In 2006, Oracle began offering Oracle Enterprise Linux (now simply known as Oracle Linux ), a repackaged version of the Red Hat Linux operating system. Oracle Linux, like all distributions of Linux under the GNU General Public License, can be downloaded and used for free, even for enterprise production-level systems. Oracle, like many other companies that offer Linux, also offers paid support contracts for the use of Oracle Linux. Oracle Linux is distributed with two separate kernels. The Red Hat Compatible Kernel is identical to the one shipped with Red Hat Linux. In 2010, Oracle announced the second kernel, the Unbreakable Enterprise Kernel , which includes enhancements designed to increase performance for the Oracle database.
In addition to its Linux product, Oracle offers the Solaris operating system, now known as Oracle Solaris . While Solaris is commonly associated with the SPARC chip architecture found in Sun hardware, it is also available for x86 and x86-64 chip architectures, such as the ones found in personal computers. Solaris is a true POSIX-compliant version of the Unix operating system.
Note
The real-world DBA
Since both Oracle Linux and Oracle Solaris can run on the x86 platform, you can download either of them and install them at home if you have a spare computer with sufficient resources. Additionally, both operating systems can run the Oracle Database. This can be a great way to learn about administering Oracle on a Unix-like environment.
Application servers provide an environment that facilitates the development, deployment, and execution of the various software applications that a company utilizes. This can include anything from simple web servers to more advanced middleware architectures that use Java and clustering for high availability. In this domain, Oracle has historically offered the Oracle Application Server, which was later incorporated into Oracle Fusion Middleware, a package of software products that facilitate business intelligence, SOA, and content management operations. In 2008, Oracle acquired BEA Systems and their WebLogic application server product. It has, since then, essentially replaced Oracle Application Server as Oracle's de facto standard.
Oracle also has a significant presence in the Customer Relationship Management (CRM) market. In 2005, Oracle purchased PeopleSoft, which had previously acquired JD Edwards. Adding these two products to their own CRM product, Oracle Applications, Oracle became a major player in the CRM market.