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Chapter 1: Introducting Oracle8i
Most everyone has heard the cliche, "information is power." And is this ever true. When you think about it, one of the most important assets of any institution is its information. For example, a typical business must keep track of its customers, orders, product inventory, and employee information for obvious reasons. Additionally, the analysis of pertinent business information can help make a company more competitive. For example, a sales analyst can use current sales data to forecast future sales and identify trends that might help to improve overall business profitability.Information Management
In today's world of high technology, computers manage most information because they make it easy to organize, store, and protect valuable data. The proliferation of powerful personal computers and networks has made it possible for all businesses, large and small alike, to quickly and safely make information readily available to people that require access to it.
Databases
Computers typically store and organize large amounts of information within a database. A database, whether or not a computer manages it, is nothing more than an orderly collection of related information. A database safely stores information and organizes it for fast retrieval. For example, a business can use a database to store tables of customer records, corresponding sales orders, product parts, and employee lists. Various workers can then use the database to efficiently perform their jobs. For example, salespeople can quickly enter or look up sales orders, advertising executives can study and forecast product sales, and warehouse personnel can efficientlymanage product inventories.
Types of Databases Databases come in many varieties. Inverted list, hierarchic, and network database models are older types of database systems that, in general, are inflexible and difficult to work with. These types of database systems were originally designed primarily for prescribed transactions that input data rather than dynamic environments where data analysis is critical.
The very weaknesses of these earlier systems are exactly why relational database systems now dominate newer information management systems. Relational databases are easy to understand, design, and build. Relational databases store and present all information in tables, an easily understood concept. Furthermore, relational databases hide the complexities of data access from the user, making application development relatively simple when compared to other types of database systems.
Object-oriented databases are a relatively new type of system that supports the object-oriented development paradigm. The primary goal of object-oriented thinking is to raise the level of abstraction so that it is more natural to design and build an information management system. For example, in an object-oriented database, complex data structures called objects closely model the entities in a business system, while methods match the business operations that act upon the objects in the system. So, rather than store tables of, say, customers, orders, and order line items, a database stores instances of customers and sales order objects. Associated methods stored in the database describe how to add, change, and delete customer and sales order objects.
Database Management Systems
A database management system (DBMS) is computer software that manages access to databases. A typical multiuser DBMS performs the following tasks, and more:
- A DBMS safely manages shared access to a single database among multiple concurrent users. For example, a DBMS locks data as users add and update information, so that users do not destructively interfere with one another's work.
- A DBMS uses computer resources wisely so that a large number of application users can perform work with fast response times for maximum productivity.
- A DBMS protects database information in such a way that it can reconstruct work lost due to anything from a simple power outage to catastrophic site disasters.
Oracle8i, Building on Oracle? and Oracle8
Oracle8i builds on the strengths of its predecessors, Oracle? and Oracle8.0. Oracle?, originally released in early 1993, set a lofty standard for high-end relational database management systems. Oracle7's many features made it a potent database server for all types of common business applications, including.