Tap the wells of legacy data using the DataFlex WebApp

Server

Legacy Applications Procedural code. Hundreds of programs in application. Years to write, debug and test. Stable and reliable. Users are well trained. Difficult to leave - Modified FMAC or DFRun. Years of data entry means big data files. WebApp Server can add tremendous value to this data.

Reports on the web. Data entry / remote access via the web. Data mining.

Environments The great news is that DataFlex data (2.3 and higher) is readily available for the web,

regardless of the deployment platform. We do not need to port the application to the NT server. Legacy application / data can reside on Novell, or UNIX servers. Client Server back-ends on UNIX will connect using protocol of Server engine. For native DF data, UNIX Connectivity products mount the UNIX file system as a NT drive.

SAMBA NFS SCO / VisionFS FacetWin

Remember opportunistic locking and readcaching always apply. If UNIX / Share locking mechanisms are in sync, then data integrity is

preserved. How can we test if the lock managers respect each other?

FacetWin Connectivity

WebApp Server is multi-threaded when processing many web requests. FacetWin bases user counting per connection, not processes, so a 1 user count

license is all that is necessary for the WebApp Server. FacetCorp offers technical support to their customers.

Data

UNIX runningconnectivity

daemon

NT4 / IISWebApp Server

1user

Keeping The Status Quo If we have a well programmed application that earns our reputation, we may be

hesitant to change the system. If we have invested a lot time or money in a system and we are unable to or

unwilling to go through it again. If we don’t want to re-train our users nor rewrite training manuals. If we want to continue to use our legacy technology in its full capacity without

modifying a line of code and have it work with latest Internet technologies.

Then the DataFlex WebApp Server is the way to go!

Benefits For Legacy DF Programmers

No longer trapped in legacy technology by a legacy system. Learning object-oriented programming is accelerated without having to master UI

sub-system messages. Implementing business rules with the DBB makes it easier to learn and understand

event programming. Solution for remote access - Client / Server architecture. Reuse business rules regardless of database engines without re-writing server side

stored procedures. Staying current with DF technology will ensure your application is current with

today’s DF technology and tomorrow's, as DataFlex evolves into the next millenium. HTML characteristics are similar to procedural DataFlex without image limitations. Ahead of the game because we know our customers, market and business rules. Get the same RAD development for the web as we expect from DataFlex tools.

Are Data Dictionaries Required? Typically reporting would be the first step. Report can be written with standard DataFlex looping control.

Repeat / Until While / Found For_all loop Even a report macro worked in the WBPO.

Data entry applications should use Data Dictionaries for the easiest enforcement of business rules in a multi-user environment.

The Easiest Way: Data Dictionaries Take advantage of the workspace concept.

Separate old development from new development. Prevents developing against live files.

Start with a bare bones Data Dictionary automatically generated by the DBB. Business rules need not be complete, add as needed for web page.

DDOs are the most manageable to develop and maintain business rules. No more searching through thousands and thousands of lines of code.

DDO ensure data integrity between WAN and LAN.

Creating Data Dictionaries Different runtimes enforce relationships differently.

WebApp / VDF runtime will check: relating field is same size and type. Uniquely indexed parent, child relates to parent, n : 1 is still the same. Look for and remove multiple relationships between two files. Start by analyzing relationships first to harness the DF methodology, rather than

fighting hundreds and hundreds of messages. Just because every file can be related, to another file does not mean they need to

be. - I usually need to remove relationships during upgrade to VDF. Use relationships for finding parents and constraining children. How To Check relationships:

DDB > Reports > Check Relationships and draw tree by hand. VDF Database Structure Viewer by Hans van de Laar

Relationship Tree

Diagram generated by: VDF Database Structure Viewer, authored by Hans van de Laar

AUX_DET (1)

PLEDGE_H (3)

MEMBER (6)

ASSESS (7)

PLEDGES (10)

CONTRIB (11)

EMERG (14)

ASSESS_P (20)

EVENTLOG (23)

FAMILY (26)

GIFTS (27)

CONTACTS (101)

NUMBERS (102)

CALLS (103)

CIRCULAR OR DIAMOND?A

B C

D

Trend In Internet growth?

For DF data, the WebApp Server is the fastest way in the word to get data on the web. If you don’t “ride the wave soon” you will miss out on a great opportunity. Gordon Bell Senior Researcher Microsoft Research points out expected Internet growth.

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