Introduction

This is a fairly simple environment for quickly creating data-driven applications, that is, graphical applications that manipulate and show info from a database. This environment differs from others in that it is focused on native GTK/Gnome support through the Glade GUI designer, and thus allows you to build user interfaces as elegant as you can make them in Glade.

At this point, this system has enough features to be adequate for creating basic form-editing and reporting applications. Multiple SQL database vendors are supported through ODBC (http://www.iodbc.org) or libdbi (http://libdbi.sourceforge.net) drivers. There is very simple db-driver infrastructure so its easy to support for additional SQL API's. The system supports all of the basic Gtk widgets, and an additional half-dozen Gnome I/O widgets, such as GnomeDateEntry.

estron is powered by an 'engine' that has some fairly generic proceedures for mapping 'fields', such as sql table columns or widget values, between each other, and also between other things, such as objects, hash tables and etc. This engine is currently being expanded so that it becomes possible to easily add support for all kinds of new object systems: i.e. for the engine to become a generic re-mapper between not just SQL and GTK but between many differnt types of object systems and data sources/sinks.

Built on top of this engine is a DWI application that parses an XML-based file, the "DWI file", that describes the connections between glade widgets and database tables. Currently, the only way to create DWI files is by hand. Unfortunately, this can be a fairly long and laborious process itself, especially when creating something a bit more sophisticated. In the future, we hope to have an extension to Glade, or possibly an extension to a database-browsing tool that will allow you to graphically make such connections. (Work has begun on such a tool, written in DWI itself).

The grim reality is that estron won't ever become popular without a graphical designer. Although fairly complex apps can be readily created using DWI, it does have a non-trivial learning curve. When we say "can be created quickly", we mean "days" or "weeks", as opposed to "months" for traditional database application development cycles. Graphical RAD tools have a way of being brainlessly pleasent to use, and give the impression of an even faster development cycle, even though the learning curve is identical.

Note that the design of the XML format is sufficiently generic that it is not directly tied to Glade. It is envisioned that it could be used to create data-driven web pages. That is, Glade is currently the only GUI driver, but other drivers for other GUI's should be possible.