From: Richard Cole <rcole@...>
Date: 2005-04-11T11:06:24+09:00
Subject: Re: Free XML Databases (with Ruby!)?

Jonas Hartmann wrote:

> I seek a way to save data into a flexible tree, this means into a tree 
> I can basically extend on each node by filling it up with multiple 
> content elements (Just compare it to a file system).
>
> First I thought, lets just take XML; then I thought that it would be 
> rather slow if I had to pass past data of - lets say a CD Image of a 
> downloadable file I stored in there - so i concluded to separate 
> structure from content/data again - but this makes it inflexible, 
> cause I just cant set a flag "fulltext-search-disabled: no" to 
> include, lets say, a really huge text document for example.
>
> Anyone got an idea? I am still planning my project, I also looked 
> around for a flexible pure OO language fitting web developers needs, 
> and found ruby =).
>
>
>
> So, anyone knows a free native XML/OO Database? I am kind of new to 
> XML structures as well, but I imagen something that works like this:
>
> - can import .xml files
> - can use a .dtd file to test the data structure of a .xml file but 
> must not!
> - can export .xml files
> - data inside the xml database is accessible (selectable) via anything
>   like xPath ( http://www.w3.org/TR/xpath ) /
>   xPointer ( http://www.w3.org/TR/xptr-xpointer/#b2b1b1a ) or so... I
>   am not yet deep into this topic.
>
> Maybe I don't need XML, and there is another way to store the type of 
> data I got. (tree-like, file-system comparable).
>
> It should work well with ruby somehow (maybe there could be any kind 
> of interface/module I can use).


This suggestion is kind of out of left field: did you consider Kowari 
(kowari.org), it's an RDF database and you can access it via SOAP which 
means a Ruby interface is not too far away. Nice thing about Kowari is 
that it integrates Lucene and has a very powerful query/inference 
language called iTQL.

I found a confusion mapping OO to XML, are the element names roles or 
types? That problem dissapears with RDF because you specify both roles 
and types, e.g. the confusion in XML:

<circle> <center x=0.4 y=0.5> </circle>
<document> <paragraph> </paragraph> </document>

There seems to be a confusion between roles and types. Circle is a type 
right? and center is a role?

regards,

Richard.