RE: DOM Implementation for realtional databases

Alexander Stiefel wrote:

> What do you think about an DOM implementation for relatiol databases, which
> maps the contens of a database to a DOM structure ? Is there a need for such
> a implementation ?

Sorry about the late reply -- I've been on vacation.

Although there has been talk of building a DOM implementation directly on a relational database (trying poking around the XML-DEV archives at http://www.lists.ic.ac.uk/hypermail/xml-dev/), I'm not aware of any implementations.

In any case, implementing the DOM on top of a database is not really related to XML -- it simply adds another interface to the database. Furthermore, it's not clear how useful this would be.  Most database applications are interested in *data*. For example, a sales order application needs a bunch of objects representing a sales order -- the overall information, the lines, the part information, and so on. But the DOM represents a *document* -- the objects represent element nodes, attributes, entity usage, etc. Thus, most database applications would simply walk the DOM tree and build a separate set of data objects, a process that can probably be done more quickly through other (existing) interfaces.

That said, I have implemented related software -- a package to transfer data between a relational database and a DOM tree. However, this is not quite the same thing as implementing a DOM tree on top of a relational database. (In particular, changes to the DOM tree are not reflected to the database and vice versa.) Instead, it is meant to be used by applications that store their data in a relational database and want to use XML as a way to transfer it. For more information, see http://www.informatik.tu-darmstadt.de/DVS1/staff/bourret/xmldbms/xmldbms.htm.

Software for transferring data between XML and relational databases is available from a number of other sources, including Oracle (http://technet.oracle.com/tech/xml/main.htm), Software AG, and the University of Wiesbaden (http://wwwnew.informatik.fh-wiesbaden.de/~turau/DB2XML/index.html).

-- Ron Bourret

Received on Wednesday, 4 August 1999 10:03:38 UTC