Here is a history of Visual DataFlex, a systems development tool which has a hugely respected and dedicated following amongst the developers that use it. These are most often developers in mid-size and small companies seeking a lower cost or more rapid alternative to Microsoft platforms such as .NET and VB. They may be commercial developers suporting multiple business clients, or working in-house on sometimes large business critical applications.
Visual DataFlex (VDF) is a database RAD (Rapid Application Development) visual studio where windows and web database applications can be designed.
"The best kept secret in database development"
Article Overview
- Where did Visual DataFlex Originate?
- What advantages does it have over .NET and VB?
- Why should I try Visual DataFlex
- Who makes Visual DataFlex?
- What support would I receive from Newsgroups/Support Groups?
- What’s the future of Visual DataFlex?
Where did Visual DataFlex Originate?
In 1981, alongside many end user development systems such as DBASE2, Sapphire, Sensible Solution, "The Last One" etc., DataFlex launched in it’s 2.0 version for DOS, CPM, and Turbodos.
The CP/M and Turbodos versions were notably robust in multi-user environments, and this later carried over into UNIX and DEC VAX releases when V2.3 arrived in 1987, and into the PC world as DOS networks came to dominate with Novell and then the Microsoft Network operating systems defining the multi-user PC environment. Although higher priced as a database engine and development platform than its peers, its specifications (especially in its multi-user capabilities) outweighed the competition and many individuals who were not programmers purchased DataFlex. Benefiting from its English like syntax these developers became faithful followers with many success stories following along and with many still active as developers 20+ years on from those early days. At one time you could neither lock up a prisoner nor park an aircraft at Heathrow without DataFlex.
If you were an accountant, sales manager, or inventory analyst, DataFlex was perfect since it was a 4GL product and handled the interface with the database included in the package automatically for you. A winning combination of work skills and easy database development combined to make v2.3 a highly successful development product. As time went by many packages written in this era were from experts in the field and while many unorthodox coding methodologies were employed, it all worked, and the resulting applications ran notably quickly! Even today, 20 years later, DataFlex 2.3 derived systems are still in extensive use, mostly (but even now, not all!) running in the current DaFlex v3.2 character mode version and quite possibly addressing industry standard databases such as MS SQL Server, Oracle, My Sql etc.
However, as with many other (now) Legacy Systems written for DOS, deployment and maintenance has become more difficult since Windows was introduced. Nevertheless, there are many DOS DataFlex applications still powering businesses across the world and most are now debating whether to port to Windows, or to the Web, while still using Visual Data Flex. The main concern of many companies is that unique and proven code which runs like lightning would be compromised by either of these solutions. This is generally a real concern but in practice of significantly less importance than users perceive - and today’s VDF offers both options working together as well as either option!
What advantages does VDF have over .NET and VB?
Imagine you are a designer of software, and a .NET development solution from Microsoft is available. First, you start with the user interface, and the tools to produce a user interface in windows/web are indeed attractive. But then, you have the job of writing an interface to the data which is a huge undertaking and requires thousands of lines of code to produce a stable application that follows the specs of database table business rules and the connections between database tables (dependencies, etc).
Now, imagine you are a Visual DataFlex designer. First, you start by subclassing (using an application or business name related class name for instance) the controls provided by Data Access Worldwide (these are true windows controls) and leave the original classes unchanged but available for future use. Then, you open the database builder which creates data dictionaries for each and every database table in your project, relate the database rules to each other (relationships are auto-generated in DF) and determine how each column of each table will appear, which validation will apply to it, and set your business rules directly in the CLASS for the table.
See how the two approaches are completely the opposite? In VDF, the detailed tedium of the minutiae of database connection is eliminated.
Visual DataFlex emphasises data validation, and the business logic required by the application when finding, clearing, deleting, and saving data. Only then do you use the Visual Studio to create the visual portion of the program which is built on a "tree" of connected data dictionary objects (instantiated business rule layers based on the classes) which allow for business rule exceptions and augmentation. Web application development proceeds on similar lines (and for the "business logic" uses the same data manipulation code). Further changes to the business rules of course can be made, and are automatically applied to the visual interface throughout the application. (If that sounds a bit "technical" don’t worry, how it all works is looked after for you.)
The advantages appear immediately:
- Data Integrity and business rule layers intertwine and this facilitates the fact that you MUST validate the data (automatically generated validation based on your rules) and synchronize data transformations together in order to save a record or records.
- The visual designer has the same classes for the most part as .NET and VB but in VDF they are tied into database definitions and immediately acquire the customised save/clear/delete/ validate/find operations that do not need further programming.
- "Visual Design" encompasses both windows GUI and Web page development, with common business code rules underpinning both. The AJAX library that is now a part of VDF (rather than a free optional component) reinforces the value of the common business rules approach to development, by building interactive daat validation and updating based on those rules into your VDF Web Application, just as is doone for a Windows Desktop application..
The combination of these advantages means that your data integrity is higher, your data operations are more eloquent, and also the design interface (now quite up to .NET standards ) is visually appealing.
The design and deploy time from start to finish is less than .NET by an estimated 40% resulting in lower cost to your customer and more winning bids for you.
Why should I try Visual DataFlex?
Business Application develppment.
First, from the above, you can see how a database oriented approach is significantly easier than other options. However, don’t download VDF to program a game! VDF is built for business applications as a specialty, so if that’s what you are programming I suggest you give it a try.
Support
Second, the VDF community is closely knit and we publish free code and add-ons, answer questions immediately and with great skill on the newsgroups . Once "on board" you will belong to an elite membership where the close relationships with other developers are both attractive and highly rewarding.
Database Independance
Third, Visual DataFlex is a transparent front end for just about any database back end you care to use, such as MS-SQL, IBM DB2, etc. (Ed:- At Asckey Data Services we can confirm "no code changes" to move between different industry standard databases. Or even to support multiple different databases in the same application.)
But if you are afraid of being sacked for using a non-Microsoft product, please disregard this article entirely!
Who makes Visual DataFlex?
The answer is perhaps surprising. Of course, Data Access Worldwide of Miami, FL, USA makes the product, but it is crafted largely through suggestions of individual developers who receive direct feedback from company representatives on our newsgroup forum, and feedback at conventions personally. Imagine that you too can shape the direction that the product flows and your actual bug reports are included with the fixes in the next release! Credit where credit due, Data Access is hugely responsive to its users.
Data Access also has worldwide distributors and is a global product used in many countries.
What support would I receive from Newsgroups Or Support Groups?
Example: In the UK, you can participate in the VDF Sig User Group (http://www.vdfsig.co.uk/) which welcomes developers and has regular meetings in person to promote camaraderie and show technical presentations on current projects by the members.
In addition, there is the Visual DataFlex newsgroup which is monitored by Data Access Technical Support to some degree, but the feedback comes mainly from globally based Visual DataFlex developers and I personally recommend this newsgroup due to the high quality support received (and given) over the years.
What is the future of Visual DataFlex?
Data Access Corp has network partners over many locations who introduce the latest features available such as SOAP, AJAX, activeX, Web Services, etc. The current version 12 (Ed- Now V15, and even further advanced in these areas ) looks very familiar to .NET developers, and this will continue, with improved (CodeJock) visual presentation classes for Windows development and an AJAX framework for Web development about to emerge.
In addition, the FREE Personal Edition which includes the entire studio and all connectivity kits is available. The promotion of this product, while being largely word of mouth keeping the tradition and nickname of the product as "The best kept secret in database programming" alive, is also finding its way onto magazine CDs.
I invite you to pop open a search engine and search for Visual DataFlex to see what all of the (not(fuss)) is about!
Author: Peter A Donovan of Applause (TM) Software
Peter has been developing custom database applications since 1982 and has migrated his development techniques from DOS/ Windows/Web and oops programming specialization through to centralized coding ("write once, use many times") in both Windows/Web and Crystal Reporting.
This article is based on Peter’s material, with minor changes for a mainly UK audience.
Our thanks to Peter for this excellent and independent view of DataFlex/Visual DataFlex. We hope that you have found this to be interesting and useful background information on the product.
Please feel free to contact us if you have any questions, whether arising from this article or from your initial explorations of VDF
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Visual DataFlex - A Product History