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From: Martijn W. van der Lee (gmane_at_[hidden])
Date: 2002-11-08 05:03:53


Currently Ditto is working though there are some areas in which it can be
improved and being a one-person-design there's bound to be some gaps, for
this I would very much like the input of some more experienced C++ coders so
I am indeed looking for team members or atleast some comments.
As for comparing it to the Relational Tables these seem to be somewhat
different reading from Arkadiy Vertleyb's mails;

- RTL uses expressions for sorting/filtering whereas Ditto uses functors.
- RTL does not seem to automatically update it's views (or whatever it is
known as in RTL terminology); when a record is added to a table (or view),
it is not immediately available in all other views based on that table.
- Ditto can stack views as to provide multiple levels of refinement of the
underlying table.
- RTL can mix multiple tables into one singular view, Ditto currently cannot
(though the architecture is capable of this).
- Ditto can assign events (using callback functors) whenever a record is
added/changed/deleted and even when other events are triggered.
- Ditto can keep a pointer to a single record by means of a tracker class
which also plugs into the event mechanism, I don't know if/how RTL handles

I may be wrong here with regards to RTL and perhaps the concepts of both
libraries can be mixed into one library, which would be ideal.
I'm also under the impression that the goals of the libraries are different,
RTL seems to want to be an in-memory relational database, Ditto tries to
provide a means of easily sharing data without a database in a GUI
Performance differences are also unknown to me and it may be impossible to
do a decent comparison if both libraries are indeed too different.

Martijn van der Lee

> You very well know that I am scouting for an in memory
> data base. I wish to use one in a future project. My
> question now is when do you think Ditto will be completed?
> Are you looking for other team members/developers?
> Also, in terms of features, how does it compare to
> other libraries such as the recently proposed Relational
> Tables by Dmitriy Arapov and Arkadiy Vertleyb?
> Regards,
> --Joel
> ----- Original Message -----
> From: "Martijn W. van der Lee" <gmane_at_[hidden]>
> Subject: [boost] Possible Boost addition; Ditto framework
> > Hi,
> >
> > I've been quietly working on a framework which I think could make a nice
> > addition to Boost. Currently it compiles on Borland C++ 5.5.1 and GCC
> > (Dev-C++/MinGW) and seems to be stable (though the testcases are not
> > implemented yet).
> >
> > In short it is an in-memory generic table and view framework where a
> > class contains records similar to a database table and "view" classes
> > contain sorted and filtered (by means of functors) version of that
> > These views are updated dynamically so adding a record to the table will
> > automatically make it available in all views.
> > Furthermore, views can be stacked to allow multiple levels of
> > single records can be selected by using a "tracker" class and events can
> > triggered on any change in the frameworks' classes by means of a
> > class.
> >
> > The original purpose of this library was to replace Borlands' VCL
> > which requires data to be located inside the class handling the visual
> > layout, this made it extremely difficult to have multiple separate views
> > the same set of data, the Ditto framework succesfully eliminated this
> > problem at the cost of recreating the visual components but with the
> > of performance, memory requirements and especially code quality.
> >
> > The project is published at sourceforge;
> > the site is a bit outdated and documentation is especially lacking, the
> > current version in CVS is stable and can be downloaded from the project
> > at
> >
> > There are currently still some minor issues with the library (mostly the
> > need to specify a dummy filter functor to views when no filter is
> > but with some help (hint! hint!) I believe the framework could be in a
> > finished state within weeks.
> >
> > regards,
> > Martijn van der Lee
> >
> >
> >
> >
> >
> >
> > _______________________________________________
> > Unsubscribe & other changes:
> >
> _______________________________________________
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