Oracle Essentials [Electronic resources] : Oracle Database 10g, 3rd Edition نسخه متنی

8.7 Object Technologies and Distributed Components

In many ways, the greater the amount of information, the more
intelligence that can be extracted from it. Integrating information
from separate systems can be an enormous task, especially because the
complexity of integration increases geometrically as more systems are
added to the mix.

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 one 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 Request Broker Architecture, a multivendor industry
standard developed by the Object Management Group (OMG) for object
interaction

Java

A popular object-oriented language

EJB

Enterprise JavaBeans, a standard architecture for computing using
business components written in Java

CORBA, EJB, and objects are covered in more detail in Chapter 13.