Re: [topicmaps-comment] mapping topic maps on a relation database

[Lars Marius Garshol <larsga@garshol.priv.no>]

* franck legoux
| 
| Does someone has a model to map "topic maps" on a relational
| database ?

* Andreas Rittershofer
| 
| This is possible, but why not to store it in an XML-database like
| Xindice? See http://xml.apache.org

You could do that, but the benefit is much smaller than it seems.
Basically you would have to create a new DTD (call it XTM') and then
transform from XTM to XTM' before storing it. Otherwise performing
simple queries like "show me all composer born in Italy" is just plain
hell to compute, since you would have to do things like merging,
following three different kinds of references etc during the query
evaluation.

Using an XTM' DTD may be a viable option, but I think you'd find XML
Query about as easy to use for querying it as SQL for querying the
RDBMS topic map. 

What you really want is a frontend that hides all the messy storage
details for you. All the topic map engines do this for you, in one way
or another. TM4J even has an XML storage option, but I don't know what
DTD that uses. The commercial ones also have RDBMS storage solutions,
but none of them publish their schemas, as far as I know.

-- 
Lars Marius Garshol, Ontopian         <URL: http://www.ontopia.net >
ISO SC34/WG3, OASIS GeoLang TC        <URL: http://www.garshol.priv.no >