In addition to these enhancements, there were a number of new features added to Oracle8:

•  Table partitioning. This is a big improvement when it comes to very large tables. Here you can divide a table into multiple sections based on some logical index value (divide an Orders table into sections based on month ordered, for example). Each section can be placed on a separate disk drive. One advantage to this arrangement is that Oracle is smart enough to know which sections are needed. When performing a query, it ignores the partitions that are not needed, thereby reducing the amount of data that must be scanned. It can also enhance reliability in that you can operate the database with a given section of a table down due to a failed disk drive or some other reason. You cannot issue queries that require information from the missing section; however, you can issue queries against the other section and add new data to another section.

•  Index partitioning. Index partitioning is similar to table partitioning described previously. Here you divide an index into multiple partitions (disks) based on the values of that index. It can be very useful for large indexes in splitting disk input/output.

•  Backup and recovery management within the server. Previous versions of Oracle relied on operating system utilities to perform backups. As databases grow, simple backup strategies are usually not sufficient to keep up with the growing data volume. To implement more sophisticated backup strategies, a knowledge of the database and how it is structured is required. In Oracle8, the database now implements a more sophisticated backup strategy, coordinated through the Enterprise Manager tool. You can use this tool to determine what has been backed up and implement the most efficient recovery.

•  Connection Manager. To implement some of the features that make better use of system resources when it comes to user and database connections, Oracle has implemented Connection Manager.

•  Security Server. Some of the problems when you start building a distributed database environment are the maintenance tasks associated with keeping each of the databases current. One of the biggest chores can be adding and deleting users in each of the databases and granting them the appropriate privileges. The Security Server centralizes this administration in a single location that can be maintained through a graphical user interface in Enterprise Manager. All databases now access this central repository for security information, as opposed to having it maintained internally. Chapter 19, “Oracle8 Administrative Requirements,” discusses administration of Oracle8 databases in more detail.

•  User-defined data types. While Oracle provides a wide range of data types, advanced users are thinking up complex data types that are combinations of some of the basic forms of data (an X-ray image with the associated patient information could be considered as a single data entry). Oracle8 allows users to define data types composed of the basic data types that are treated as a single object.

•  Object-oriented extensions. Oracle8 implements a number of features found in object-oriented programming, including data methods and data types. These data and methods are treated as a grouped entity (object).

•  Data cartridges. Users have long used Oracle database to write applications. However, many people today want to tightly integrate their software with Oracle. A data cartridge can be configured to handle more complex data types (video, for example) or to provide extended software (image recognition system software). The key here is that data cartridges are tightly connected to the database through an application programming interface (API), as opposed to just connected through client-server data access mechanisms.

The Oracle8 Product Family

Oracle8 is actually a family of products. It includes the software that provides database management services. It also includes a series of tools that allow you to access and update the data in the database (SQL*Plus, Loader, Import, and Export). It also includes a series of administration tools to help keep the database operational and perform routine administrative tasks (Server Manager and Enterprise Manager). Finally, there are a number of optional components (enhanced replication and parallel server among them) you can purchase as additions to the basic Oracle8 server package and that allow you to perform specialized functions. Chapter 4 will go over these options, tools, and components in more detail.

Fitting Oracle8 into an Application Environment

One of the purposes of this book is to provide you with an understanding of Oracle8 so you can integrate it into your application environment. There are a number of different architectures Oracle8 will support. You can use Oracle8 as a traditional host-terminal system where the software is written to run on the server using some character mode interface. You can also implement Oracle8 using a client-server function with a PC providing the front end and the server providing database management functions. You can also implement a Web server or an application server where you have three different computers providing services that are part of your application. This book will discuss the technologies associated with these environments and how to implement them so you can decide which ones best fit your needs.

Summary

This chapter provides a brief introduction to Oracle8. It highlights the new functions that are provided by Oracle8. This should help those already familiar with Oracle7 to focus on those areas that have changed. This chapter also provides a brief overview of the history of the Oracle Server product line and some material on product direction that will be useful when trying to understand why certain features have been added.