Oracle Essentials: Oracle9i, Oracle8i and Oracle8, Second Edition

Object Technologies and Distributed Components

Companies spend a great deal of time and money implementing systems for specific functions, such as human resources, financial management, manufacturing, or purchasing. While messaging technologies can assist with interfacing different systems, online interaction is often needed as well. For example, if the human resources system maintains information about the company’s employees (such as the department in which they work and their role), ideally the purchasing system could access the data in the HR system online at the time purchases are being made. At this point, the purchasing system could determine the spending limits of the purchaser and to what department the accounting should be tied. In practice, these online interfaces are difficult to build because they require the systems to agree, and remain in agreement, about how to communicate. Each system has proprietary application programming interfaces (APIs) that allow other systems to communicate with them. These specific, and often conflicting, APIs limit the reuse of the functionality within each system.

Object technologies offer a compelling solution: systems communicate by invoking methods on objects instead of by calling specific APIs. For example, if you want to check the department of a user, you make a standard object call to the employee object managed by the HR system.

Oracle8i and later versions support a number of object technologies, including:

CORBA

The Common Object ...