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CHAPTER 1

Introduction to Oracle
Tools

This chapter introduces you to the Oracle Corporation and its main development products: the Oracle7 database and the Developer 2000 Tools Set. They are the main tools for developing an Oracle relational database.n

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Oracle the Company

Oracle began in the early 1980s as a relational database company with very few software products. At the time, relational databases were in their infancy. The pioneers that formed Oracle foresaw that the computing industry would move toward relational databases. During this period, IBM (Big Blue) dominated the industry with a very good relational database called DB2, but it operated only on their hardware. Since Oracle was a competitor, it was forced to take a different strategy. Oracle developed an open-system concept whereby the Oracle database could be used on virtually any computer. This was an attractive option for the non-IBM vendors of hardware and software. It also was attractive to the customers in the industry that didn't like being locked into IBM.

Today, Oracle is one of the largest companies in the industry. It has a wealth of products that revolve around their Oracle7 database product. Their main products are the Oracle7 database, Developer 2000, and Designer 2000. Oracle also provides consulting services for the planning, development, and implementation of systems.

The company is based in Redwood, California. It does business in more than 90 countries and has software that runs on scores of computers. Oracle also is a major player on the information highway.

Oracle7—Oracle's Database Product

Oracle7 is Oracle's relational database product. The product runs on scores of computer platforms and is the database of choice for many software vendors. Oracle7 supports several configurations and can be used in a host-based configuration where the user is connected to the same computer that contains the database. Mainframe applications would be an example of this type of configuration. The mainframe contains the database and the software. A dumb terminal or a PC acting as a terminal accesses the mainframe. In contrast, Oracle7 also supports client/server applications where the database is contained on a server and the applications on a different platform. The application software and the database are accessed through the use of a network. Oracle7 also supports the distributed processing configuration, which means that the database may be spread across multiple platforms. For instance, part of the database is located in Los Angeles and the other part in Portland, Maine. These last two configurations are powerful features in an era of rightsizing computers and distributed data processing.

Oracle7 also has a number of significant features, including extensive security mechanisms—sensitive data can be safeguarded through the use of privileges. Also, the database administrator can grant privileges to view, update, or delete records. There are myriad other privileges available to the administrator to control access to the database.

The database also has sophisticated backup and recovery procedures that minimize the chance for data loss. Every transaction made against the database is stored in archive files. Thus, when the need arises, Oracle can restore the database. Oracle7 also has flexible space management tools that allow the database administrator to place limits on the size a database can grow. Finally, the Oracle7 database supports open connectivity, which means that you can access

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Oracle 7—Oracle's Database Product other vendors' databases through the product. Oracle7 can access databases such as DB2, Sybase, or Microsoft's Access. In addition, Visual Basic and a myriad of other software products can use Oracle7. The ability of multiple software packages accessing a commom database is an important feature for a company that does not want to worry about being locked into a product.

Oracle7 has a number of important components, one of which is PL/SQL, or Oracle's procedure language. PL/SQL performs functions similar to other languages, such as C, FORTRAN, COBOL, and BASIC. PL/SQL is a very easy and powerful language to learn. I often use it to convert data from one system to another.

The Oracle7 database provides you with tools to develop stored procedures. These procedures, stored in the database itself, consist of PL/SQL programs or scripts that perform specialized functions such as printing a letter to customers thanking them for subscribing to a service. These procedures are triggered or initiated by transactions that occur in the database.

Another component is database triggers, which isPL/SQL code stored in the database that is fired when events such as inserting, deleting, or updating records occurs. Oracle7 also allows you to group procedures into packages. The procedures also are stored in the database.

The database also has a distributed option that allows the data to reside in numerous locations. This makes the location of the data transparent to the user. In addition, there is a parallel server option. Some computers are clustered, which means that they each have their own memory, but have a common storage device. This option allows Oracle7 to operate within this configuration.

Oracle8—The Next Generation

Oracle8 is Oracle's next generation database that will eventually replace the Oracle7 installations. It is an object-relational database, which means the database is a relational database with object-oriented properties. This type of database allows developers to migrate their existing applications without rewriting them. When the time is ready, the applications can be converted to use the new object technology. This makes Oracle8 upward compatible with existing databases. This is a safe approach by Oracle. A drastic shift from the mainstay relational database would likely cause Oracle to loose market share. I believe that people like to play it safe and loathe uncertainty. Object-oriented technology offers some excellent benefits for the future and I applaud Oracle's position of gradually moving the industry in this direction.

This book is primarily a development book. It follows the traditional relational database design used for many years. The concepts are employed by using an Oracle7 database. They will also be valid using the Oracle8 database. At key places in the book, I will explain some of the new features of Oracle8. The most important of these features are new datatypes that allow the database to hold new objects such as images, video, and spatial data. Oracle8 also has capabilities for the support of database warehouses. These features do not play a role in this book. The purpose of this book is to identify and discuss the tools needed to develop the normal everyday type of system commonly used in a place of business. These are the types of systems a developer will spend most of the time implementing.

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