jWWWData: a World Wide Web JDBC Data Base Client


Overview

jWWWData is a general multi-purpose JDBC Data Base Client that can be accessed via an HTML browser.

jWWWData interfaces with all the JDBC (or ODBC) compliant Data Base Management Systems. jWWW Data is the combination of:

jWWWData Components

jWWWData HW
Architecture

jWWWData Architecture (the hardware point of view)

From an hardware perspective jWWWData is a JDBC Data Base Client running on a particular machine (where the WWW server is located), connected to the Web. All end users interact with WWW Data from other machines, also connected to the Web. The WWW Data Man Machine Interface runs on these second machines and gives the end users the feeling they are operating a local application. The actual Data Base Management System, the JDBC Server, is located on a third machine and is connected to jWWWData via the JDBC connection on an internet/intranet communication link.

To better understand how jWWWData works it is necessary to take into account its software architecture.

jWWWData SW
Architeture

jWWWData Architecture (the software point of view)

jWWWData is based on a three levels architecture:

Requests from the end users travel from the Web Browser to the WWW Server via the HTTP protocol. On the WWW server the users requets are passed to jWWWData main application via the CGI protocol. Inside jWWWData the user requests are translated into JDBC compliant (i.e. ANSI SQL2 Entry Level) requests and passed via a JDBC compliant internet/intranet connection to the Data Base Server. When needed the JDBC requests can be translated by the JDBC-ODBC driver into ODBC compliant requests and then passed on to an ODBC compliant Data Base Server.

The results of the queries entered by the end users travel along the same communiation path, only in the opposite direction.

On the end user's side there is no particular WWW Data application. The standard WWW Browser is used to handle the Man Machine Interface.

NOTE: although jWWWData has been designed to be used in a distributed environment, it can also be used on a single machine. In this case the WWW Browser, the WWW Server and the Data Base Server sites coincide.

With this background knowledge, it is now possible to examine in details all the jWWWData Components.

The JDBC/ODBC Compliant Data Base System

jWWWData requires an external JDBC/ODBC compliant Data Base Management System. A list of these databases can be found here. jWWWData has been tested with NCSA's Decibel and Microsoft's Access. Data publishers can select the Data Base Management they prefer/use.

The CGI Application

The CGI Application (swwings.jWWWData.jDCGI) is the core of jWWWData. This application receives the end user's requests, via the HTTP connection and the WWW Server, translates them into JDBC compliant SQL queries and sends them to the actual Data Base Management System. Results from the Data Base server are collected by this CGI, organised as HTML output and sent back, via the WWW Server, to the end users' WWW Browser.

The Man Machine Interface at the end user's site is generated by this application; i.e. all the forms, tables that the end users see do not exist as static files in some remote location, but are dynamically generated by the swwings.jWWWData.jDCGI when needed.

jWWWData Tools Set

jWWWData Tools Set is a collection of applications used to define the data base, create it and maintain it.

jWWWData Features

jWWWData features are listed below following the perspectives of the two different users types (the data publishers and the end users).

The Data Base Publisher Point of View

The End User Point of View