The application server technology has also had a profound effect on the landscape of the PB marketplace. When Sybase Enterprise Application Server (EAServer) introduced support for PB objects as CORBA-compliant components, the power of the PB development environment for RAD programming was extended into the middle tier of the application.

Today, PB components are completely interoperable with any other CORBA components supported in EAServer, including COM, CORBA, C++, J2EE, and Java. Furthermore, EAServer provides an ideal execution environment for mixed-language development and allows organizations to capitalize on the return on investment of their prior applications developed in PB, and also opens the door to multivendor development through its support for the latest technologies, including XML and SOAP Web services.

What Is the Return on Investment?
As the requirements of an organization change to take advantage of the power of the Internet, it is important to determine the best way to receive dividends from existing software applications. One of the basic premises of achieving return on investment in software development states that it's faster and more cost effective to reuse an existing application than to redevelop an application from scratch. A competitive edge can be obtained by this reduction in the time-to-market and the associated cost of development. If an organization has made a significant investment in PB, the ROI can be measured in the following ways:

Ability to Reuse Existing Code
There are many PB objects that can be reused in a Web environment with little or no modification. The ability to reuse existing code, such as existing business logic, window layouts, and the associated database model and stored procedures, can eliminate months or years from the software development effort. The resulting time savings convert directly into cost savings for the organization that can add up to millions of dollars for large applications.

Business Logic
The business rules that are unique to each organization are a key component of any software application. In many cases, the only place the business logic is fully documented is in the application. Leaving this code behind in the move to the Web would be costly, and re-implementing it in a new environment can be both error prone and time-consuming.

Instead, the business logic can be rehosted as CORBA components that can be called from various languages and platforms. While the location of the business logic moves from the client machine into the application server, the PB code does not have to be significantly modified, reducing the possibility of introducing new software defects into the codeline. One of the greatest justifications for the ROI of PB applications is that nearly all of this business logic is reusable without significant modifications.

In addition, by moving the business logic into the middle tier of the application, the business rules are fully accessible to the entire enterprise as CORBA components or SOAP Web services. The exposure of these business rules allows the organization to continue to integrate disparate systems into true enterprise-wide applications. This extends the current business rules written in PB to the entire enterprise and enables the organization to react to future changes in the business requirements.

DataWindow Technology
One of the most powerful features of PB is the DataWindow technology that is the foundation of any application built in PB. The data-aware DataWindow object combines the visual presentation of the window with behind-the-scenes information required to update the database into a single object-oriented control that is unmatched in the industry. The DataWindow also tracks which data has been modified and can translate the data result into the latest technologies including XML, browser-neutral HTML/JavaScript, and standard file formats like Adobe PDF and Microsoft Excel.

The DataWindow alone comprises over half of most PB applications and provides the key foundation to migrating existing applications to the Web. Re-creating existing screens as HTML and JavaScript without a tool is an enormous task and should not be undertaken lightly. Especially since the existing DataWindow layouts and table structures can be reused in components that are moved to the middle tier, eliminating the need to redesign and recode significant portions of the application. The end result is that existing PB applications can be migrated to the Web in very short time frames.

In the past, many Web applications have been largely read-only or only allowed updates to simple forms. Today, by combining the ability of the PB DataWindow to manage and update large results with the ease of constructing complex windows and forms, the type of application that can be easily constructed on the Web has been expanded to include heavy-duty data-entry applications that were previously only available in the client/server environment.

Database Stored Procedures, Embedded SQL, and the Existing Data Model
PB has traditionally been database agnostic but tightly integrated with database servers to provide rich database applications through the use of database stored procedures and embedded SQL that references the existing data model. The existing data model does not have to be modified to support a Web application and all the database stored procedures in the database and embedded SQL in the PB applications can be reused in the Web application with little or no modification.

Ability to Move to the Web Without Significant Retraining Costs
In any organization, among its most valuable assets are the people who make up the organization and the knowledge they possess about the day-to-day business activities that the organization completes. The current development staff has detailed knowledge of the numerous software applications and the automated business rules that support the organization. The ability to maximize the current staff's knowledge about the existing application when migrating it to the Web, without incurring significant retraining costs, can contribute significantly to the ROI.

When migrating PB applications to the Web, some new skills are required, such as knowledge of HTML, JavaScript, JSPs, and component-based development. The steepest and most difficult part of the learning curve is component-based development and how to deploy the components to application servers. The best practices in component development are largely language independent and it's generally accepted that it's easier to teach someone a new subject if it's taught in a programming language that's already well understood. Experienced PB developers can easily become experienced PB component developers in three months or less, compared to the 12-18 month time frame that it takes to become an experienced component developer and learn the nuances of a new language at the same time. This reduces the training time by 9-15 months, and the savings can directly impact the organization's ability to lower the time-to-market of the Web application and significantly increase the ROI of PB.

In addition, the PB IDE allows developers to develop HTML, JavaScript, and JSP-based Web applications without leaving PB. The PB IDE has many wizards that lead new developers through the process of creating new components and has the ability to drag-and-drop HTML, JavaScript, and JSP language elements directly into source code. It also has a WYSIWYG approach to Web development that allows the developer to see the layout of the pages as they are being developed. All the features of the PB IDE help lower the learning curve and reduce the cost and time to bring Web applications to the marketplace.

Ability to Integrate with Other Technologies
In today's technology marketplace, things are changing quickly and it's important to stay up-to-date with the other technologies. PB has long been known for its ability to work with any of the major database vendors, and that strong database support continues today. PB currently supports native drivers to all the major database vendors and works with any ODBC-compliant datasource. PB also has a history of openness through strong support of other client applications through the use of standard datatypes and support for Microsoft OLE to allow applications to communicate. PB has continued to expand the openness of the product with the addition of bidirectional XML support and the ability to act as a client to EJBs and Web services.

As the primary host for PB-based Web applications, EAServer follows in the Sybase tradition of open products by providing support for more component models than any other application server (PB, J2EE, Java, CORBA, C/C++, COM) with full interoperability between component models, and it's database-agnostic. EAServer also offers many common services necessary to support enterprise Web applications, including transaction management, advanced performance management, messaging, and clustering capability, which provides load balancing, high availability, and failover. It's the leader in standards and role-based security and protects critical data while in transit and when stored with support for SSL and X.509 digital certificates. EAServer also provides a full-featured Web server and plug-ins for major Web servers including Apache, Netscape, IIS, and iPlanet.

PB is tightly integrated with EAServer, allowing point-and-click development and deployment of Web applications that rely on the power of the DataWindow under the covers while exposing business logic in industry-standard ways that are accessible throughout the enterprise. Together, PB and EAServer collaborate to provide an open and flexible environment for integrating applications built on the latest technologies, including Web services, XML, J2EE, HTML, and CORBA while still maximizing the ROI for applications developed in PowerBuilder.

Summary
PB has helped thousands of organizations develop a half-million production applications by providing open and flexible technology. The PB technology has continued to be enhanced to ensure it stays open and compliant with the latest technologies, including XML, JSPs, EJBs, and Web services.

EAServer hosts more component types than any other application server and provides component interoperability that's ideal for mixed-language applications. The added support for the latest technologies, including Web services, XML, J2EE, HTML, and CORBA, helps ensure that enterprise Web applications built using EAServer are open and flexible.

When used together, PB and EAServer collaborate to provide the ability to reuse existing code, to move to the Web without significant retraining costs, and to integrate with other technologies. PB and EAServer allow the organization to maximize the return on investment in PB and position the organization for the future.