tailieunhanh - Object-Oriented Database Systems: Promises, Reality, and Future

Simple, predictable, flexible, and the most comprehensive support policy available, the Oracle Lifetime Support Policy helps drive your business success. Oracle’s industry- leading support policy covers your entire technology environment, from database to middleware to applications—an industry first, only from Oracle. Oracle’s Lifetime Support Policy also puts you in control of your upgrade strategy. Our flexible support policy stages make it easier for you to plan and budget for Oracle’s exclusive product upgrades. You’ll enjoy continued peace of mind, knowing that we’ll always be there to support your business. When it’s time to upgrade, you’ll have rights to major product. | Object-Oriented Database Systems Promises Reality and Future Won Kim UniSQL Inc. 9390 Research Blvd. Austin Texas 78759 Abstract During the past decade object-oriented technology has found its way into programming languages user interfaces databases operating systems expert systems etc. Products labeled as object-oriented database systems have been in the market for several years and vendors of relational database systems are now declaring that they will extend theữ products with object-oriented capabilities. A few vendors are now offering database systems that combine relational and object-oriented capabilities in one database system. Despite these activities there are still many myths and much confusion about object-oriented database systems relational systems extended with object-oriented capabilities and even the necessities of such systems among users trade journals and even vendors. The objective of this paper is to review the promises of object-oriented database systems examine the reality and how their promises may be fulfilled through unification with the relational technology. 1. Definitions Object-oriented technologies in use today include object-oriented programming languages . C and Smalltalk object-oriented database systems object-oriented user interfaces . Macintosh and Microsoft window systems Frame and Interleaf desktop publishing systems etc. An object-oriented technology is a technology that makes available to the users facilities that are based on object-oriented concepts . To define object-oriented concepts we must first understand what an object is. The term object means a combination of data and program that represent some real-world entity. For example consider an employee named Tom Tom is 25 years old and his salary is 25 000. Then Tom may be represented in a computer program as an object The data part of this Permission to copy without fee all or part of thia material is granted provided that the copies are not made or distributed .