Hi Sascha, thanks for your answer. The activity will help pupils to train their knowledge, for example vocabulary, using a modified Leitner System (<a href="http://en.wikipedia.org/wiki/Leitner_system">http://en.wikipedia.org/wiki/Leitner_system</a>), like in many flashcard programs (<a href="http://en.wikipedia.org/wiki/List_of_Flashcard_Software">http://en.wikipedia.org/wiki/List_of_Flashcard_Software</a>). Within the database, I'd like to store information about all the flashcard-questions one ore more pupils are training: For each pupil and flashcard, I want so store e.g. 1. Time of last revision of a flashcard/and or time of next scheduled revision. 2. Level of training for that card. 3. Direction of training it has been asked the last time (eg. English-German or German-English) ... So most of the database operations will be selects (to find the flashcards to be trained, or to compare the training level of a single flashcard for different pupils) and updates (to update the stored parameters for a flashcard/pupil-combination). When the pupil(s) is/are training on several locations, the data must be synchronized between the locations and/or be stored centrally at a place that can be accessed from every location the pupils are training on. JSON seems to rather be a data-interchange format than a database system? >Start with something you either already know well (including the >limitations and bugs) or is mature and understood by someone you can ask. I thank you especially for this advice - I like it very much. I always tend to use too many new technologies and end up frustrated by fixing bugs in my dependencies.. Johannes. <div class="gmail_quote"> 2010/5/27 Sascha Silbe <<a href="mailto:sascha-ml-ui-sugar-devel@silbe.org">sascha-ml-ui-sugar-devel@silbe.org</a>> <blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"> Excerpts from Johannes Ponader's message of Thu May 27 18:52:18 +0000 2010: <div class="im"> > I'm working on a vocabulary/maths/knowlegde training activity, first > releases under <a href="http://git.sugarlabs.org/projects/honeypot" target="_blank">http://git.sugarlabs.org/projects/honeypot</a> > > Now I want to store user data inside a database and have to make a decision > which database I should use. > > Would you be so kind to share your advice/experiences? Is there any > "standard" so far? </div>There are about as many "standards" as there are different programs. ;) As always, it depends on what exactly you'd like to do. For a start I can recommend JSON (used by several activities, with a little trick it will work both on the original/old OLPC builds and recent systems) and sqlite3 (included with Python 2.5+, so it should be available on any build shipping Sugar 0.84+). <div class="im"> > If you don't come up with some other ideas, I would tend to use buzhug ( > <a href="http://buzhug.sourceforge.net/" target="_blank">http://buzhug.sourceforge.net/</a>), as it's stated to be fast, pure-Python and > intuitive. </div>Looks nice and since it's pure Python you could just include it in the bundle, no dependency issues. But I'd be wary of using a lot of new technologies: you might end up failing just because there are too many bugs in parts you rely on. Even Xapian, something I'd call reasonably mature, has bugs that stalled my version support work (and thus my thesis) considerably. Start with something you either already know well (including the limitations and bugs) or is mature and understood by someone you can ask. If you elaborate on what exactly you're trying to achive - including where and when you'd like to store/retrieve what and how (your activity description is very vague), we might be able to provide some more specific advice. Sascha -- <a href="http://sascha.silbe.org/" target="_blank">http://sascha.silbe.org/</a> <a href="http://www.infra-silbe.de/" target="_blank">http://www.infra-silbe.de/</a> _______________________________________________ Sugar-devel mailing list <a href="mailto:Sugar-devel@lists.sugarlabs.org">Sugar-devel@lists.sugarlabs.org</a> <a href="http://lists.sugarlabs.org/listinfo/sugar-devel" target="_blank">http://lists.sugarlabs.org/listinfo/sugar-devel</a> </blockquote></div> -- Johannes Ponader 0162/94 64 94 0