QOF provides a set of C language utilities for performing generic
structured complex queries on a set of data held by a set of C/C++
objects. This framework allows programmers to add query support
to their applications without having to hook into a SQL Database.
QOF provides the framework, the new QOF XML backend (QSF) provides
the off-line storage and a format for a data stream between different
applications, including converting QOF objects.
Estron 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
form-editing and reporting applications. Multiple SQL database vendors are
supported through ODBC or libdbi drivers. There is a 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' (libestron0) that has some fairly generic
procedures 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. In a certain sense, the engine can be thought of as an
Object-to-Relational Mapping (ORM), mapping SQL to several object systems,
including Glib GObjects and QOF. This engine has been designed so that it
becomes easy to add support for all kinds of new object systems: i.e. for the
engine to be a generic re-mapper between not just SQL and GTK but between many
different types of object systems and data sources/sinks.
Built on top of this engine is the estron application that parses an
XML-based file, the "estron file", that describes the connections between glade
widgets (or objects in general) and database tables. Currently, the only way to
create estron 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 estron itself).
QuickList is likely to become a user interface for creating estron files once it
migrates to alioth from Sourceforge.
