By Raghuram Bala.
Questions regarding this article should be directed to the author at firstname.lastname@example.org.
PowerBuilder from Powersoft owns about 50% of the market in the client-server tool market on Microsoft Windows. It has gained mass appeal with an easy-to-use scripting language, high degree of object orientedness, tight database integration, and support for team development. Now Powersoft has released Unix and Macintosh versions of its flagship product for cross-platform development.
Will it draw converts in the Unix arena? Who is Powersoft targeting? Who competes with it and how does PowerBuilder stack up? Answers to these questions and more below....
The move to client-server computing began in the late 1980s, and what started as a trickle has turned into a flood with the vast majority of corporations right sizing their computer systems. The days of proprietary systems were replaced by open systems bearing industry standard hardware and software. Among the catalysts for this paradigm shift were cheaper personal computers and workstations, and increasingly computing power on the desktop as a result of leaps in microprocessor technology.
In the business computing arena, the Windows operating system from Microsoft captured the giant's share of the market leaving OS/2, DOS, Unix and others to share among the spoils. Graphical User Interfaces (GUIs) have been around since the late 1970s resulting from pioneering research from Xerox's PARC Labs and eventually gaining commercial appeal in the form of Apple's Macintosh line of computers. However, it was Microsoft that helped bring GUIs to the masses aided by low cost PCs bundled with the Windows environment.
The native language of Windows is the Windows API, and early development on Windows was limited to C-language programs with API calls. As many discovered soon, it was an onerous and arduous task to develop even simple programs using this technique. In addition, many corporate entities had bigger needs like accessing large databases from their desktops, creating reports, sharing data between applications and so on. Hence, the need arose for industrial strength tools to mask the complexity of the Windows API, and to provide powerful mechanisms such as tight integration with relational databases, transaction management, and configuration management for team development. These were features that mainframe users had come to expect and PCs had to catch up or lose their appeal. A wave of client-server tools on PCs emerged in 1992 that included Visual Basic from Microsoft, SQLWindows from Gupta, and PowerBuilder from Powersoft.
All these products use proprietary scripting languages that are easy to learn and have powerful capabilities suited for programmers of business applications in enterprises.
In the last four years, PowerBuilder, Visual Basic, and SQLWindows together with new entrant Delphi from Borland International have dominated the client-server tools arena on Windows. In the same period of time, many have discovered the strengths and weaknesses of the client-server architecture as a whole, and likewise the limitations of the above mentioned products. All of these tools thrived in two-tier client-server architectures. In the purists' viewpoint, client-server refers to two pieces of software, namely the client, which makes a request that is handled by a another piece of software on the server. In most implementations in corporate America however, client-server has translated to a GUI program that handles presentation and application logic ``talking'' to a database server. This architecture is also known as the ``fat'' client architecture.
This architecture has its weaknesses on PC platforms, namely:
With two-tier client-server computing hitting a performance and scalability wall, many of the tool vendors quickly realized the need for scalability in their products. This led to N-tier client-server architectures where the application logic is no longer bundled in with the presentation layer, but instead is kept separate. The communication between the presentation layer and application layer is through remote procedure calls or messaging. This architecture has the advantage that one could leverage the best presentation tool without affecting the application logic. A case in point would be the sudden popularity of the World Wide Web as a presentation layer. Companies using the N-Tier architecture could now use Web browsers as their presentation layer and hook into existing application logic easily without major reinvestment.
Powersoft's focus has always been on corporations and the need to build client-server applications rapidly with solid database integration. It is not a tool aimed at research laboratories, academic institutions, or other sectors of the market. That does not mean that it does not have the capability to build non-database applications.
With N-Tier client server gaining immense popularity, Powersoft has attacked the problem in two ways:
With the Unix client-server market, PowerBuilder faces off with Unify Vision from Unify Corporation, Progress ADE from Progress, JAM from JYACC, and Elements Environment from Neuron Data. Although these tool vendors have been around for a number of years, they have not enjoyed the media coverage, popularity, and industry support that PowerBuilder has garnered in the last few years. This is not to say that their products are inferior, but the market usually follows the market leaders.
With Sybase acquiring Powersoft in 1994, both companies benefited from the strengths of the other. The Powersoft acquisition made a Sybase a ``complete'' client-server company providing client application development tools as well as back- end database server tools. Powersoft, on the other hand, gained Sybase's marketing muscle, distribution channels, and a company that has a solid reputation for technical excellence. Also, on Unix platforms, Sybase's database products are extremely strong which aids Powersoft's move to Unix.
What about conventional X Toolkits such as Xlib, Xintrinsics, Motif, and others? When coding for sheer performance, the X toolkits would definitely beat PowerBuilder or any other similar tool. However, in business applications, development cycles tend to be short and rapid application development with tight database support is a must. In this scenario, tools like PowerBuilder do very well.
Powersoft's approach on the Unix platform is three-fold:
PowerBuilder's application architecture consists of seven classes:
PowerBuilder supports object-oriented programming by providing mechanisms for encapsulation, inheritance, polymorphism, and dynamic binding:
Function overloading is also supported in that more than one function with the same name can exist within a class. For example, we could have both:
void foo(char a) int foo(int a, double b)
real Polygon::Area(real a, real b) return 0; //place holder real Triangle::Area(real h, real w) return (0.5 * h) * w; real Rectangle::Area(real l, real b) return (l * b);
In the following code, the
Area() function of
Rectangle would be called although this is not known at
compile time (Note that this syntax is from PowerBuilder
Polygon a String b b = "Rectangle" a = CREATE b a.Area(5, 4);
One of the weaknesses of PowerBuilder is that the development environment is controlled by the tool. For example, if you inherited Window B from Window A, and later realize that you need to inherit Window C from Window A and Window B from Window C, there is no simple way to accomplish this inheritance. In a true object-oriented language, such as C++, one would easily do this by changing the source code. In PowerBuilder, inheritance is achieved via the development environment and one actually does not directly interact with the code that is generated. In addition, the code that is generated does not have a published grammar. This prevents one from building code generators and conversion utilities to and from PowerBuilder. For example, if you wanted to convert a PowerBuilder screen to an HTML Web Page there is no simple method because there is no PowerBuilder grammar whereas HTML is a published standard.
Hence, rapid application development without the ability to manipulate the underlying code and development environment directly has severe limitations at times. The fact that Powerscript, the language of PowerBuilder, is a 4GL and non-standard has drawbacks in terms of performance and limiting its appeal to a wider audience.
PowerBuilder for Unix is a solid product and should capture a significant market share on Unix for business application development. Competition in the Unix marketplace stacks up well against PowerBuilder in technology. However, the marketing muscle of Sybase and Powersoft and the fact that PowerBuilder's ease of use, object-oriented programming paradigm, and rapid application development capabilities would be hard to overcome.
To obtain more information on PowerBuilder for Unix, you can contact:
Powersoft Corporation 561 Virginia Road Concord, MA, 01742-2727, USA General Info: (508) 287-1500 Sales: (800) 395-3525 Web site: http://www.powersoft.com/
Last Modified: Saturday, 03-Feb-96 06:52:40 PST