|Visual Basic 6.0 Professional Edition|
Microsoft Corp., Redmond, Wash.;
Pros and cons:
+ Excellent rapid programming environment, good
run-time performance, good database support, useful for Web as well as standalone
Less object-oriented than Delphi and less
portable than PowerBuilder
Windows 9x or Windows NT, 32M RAM and 100M free storage
Visual Basic 6.0 is an easy Microsoft Windows programming environment, well-suited to
casual programming. The most common application developed with Visual Basic is a form or a
collection of forms that connect to a database.
Visual Basic programmers typically build applications by adding controls to forms and
setting their properties. A relatively small amount of Basic code then defines the actions
that tie the controls together to make the application work.
During development, Visual Basic runs its code under an interpreter. For production,
the code is compiled. Early versions of the language could compile only to pseudo-code, a
compact abstract instruction set. P-code execution was faster than interpreted
executionfast enough for user interface tasks, but not nearly fast enough for, say,
Visual Basic 5.0 added a native code compiler, which solved the speed problem nicely.
It also gained intelligent code completion and the ability to produce ActiveX controls as
well as standalone applications.
Visual Basic 6.0 retains all the good features of Visual Basic 5.0 and vastly improves
the database and distributed application support. It also adds two kinds of Web targets:
Microsoft Internet Information Server applications for any Web browser, and Dynamic
Hypertext Markup Language creation of client-side Web applications that work only with
Internet Explorer 4.0 and higher versions.
The improved database support will please most users. Data sources and data
environments are now reusable components. You can easily browse database schema, create
hierarchical views of data, and use them to build data forms and reports quickly. You also
can create data sources visually and drag and drop them into forms.
Most controls are now data-aware. Instead of having to write code, you bind controls to
data by setting two properties. Nor is it necessary to leave Visual Basic to create
reportsthe new report designer is fully integrated with the environment.
Visual Basic 6.0 can handle midtier and server objects as well as client programs. It
can help produce components for Microsoft Transaction Server and Microsoft Message Queue.
It even enables debugging of MTS components. The new packaging and deployment Wizard makes
it easy to post components to a production server. And the Visual Component Manager
conveniently tracks and reuses application components.
The addition of Web classes opens up a way to produce Internet Information Server
applications in much the same way developers produce conventional forms applications.
Instead of forms, a Web class application uses HTML pages and handles events with code
that resides on the Web server. Web classes provide a way to move existing applications to
the Internet, and a way to use Visual Basic skills to make browser-independent Web apps.
The biggest problem with server-side Web applications is performance. Any response to
the user requires a potentially lengthy round-trip to and from the server.
Client-side Dynamic HTML with scripted logic gives better response time but restricts
the choice of browser and relies on interpreted scripting languages, which have limited
run-time speed and scant development tool support.
Visual Basics Dynamic HTML page designer combines Dynamic HTML with compiled
Component Object Model Dynamic Link Libraries written in Basic. The DLLs run on the client
fully compiled to native code, so they can be very responsive to the user.
Visual Basic competes primarily with Inprise Corp.s Delphi and PowerSoft
Corp.s PowerBuilder. All three have drag-and-drop programming environments, although
each maintains its own unique language.
Devotees of object-oriented programming might prefer Delphis Object Pascal
language for its inheritance ability and strong typing. Those who need to port their
applications beyond Windows might prefer PowerBuilder.
Most casual Windows developers, however, will find that Visual Basic meets their needs
extremely well. The programming environment and the language are both very easy to learn,
the package has most of the user interface components you are likely to need, and the
third-party support is unparalleled.
Visual Basics database support is now almost as good as PowerBuilders,
which is saying something. The database tools in the Version 6.0 Professional Edition are
more than adequate for PC and light client-server database application development. Extra
tools in the Enterprise Edition encourage serious client-server database design and
If you need to produce custom programs for in-house use quickly, Visual Basic should
probably be your first choice.
Martin Heller is a software development consultant and writer in Andover, Mass.