Re: Against the Grain: Pascal commentary about XML and databases

[Jonathan Robie <Jonathan.Robie@SoftwareAG-USA.com>]

At 12:37 PM 6/28/2001 -0700, Ken North wrote:

>In the spirit of listening to both sides of an argument -- Fabian Pascal
>apparently does not agree with Rick Jelliffe's assessment of XML and data
>management or an article of mine about Schema and XQuery:

I'm confused in his earlier article, Fabian makes an argument that should 
lead to the conclusion that XML databases are an important thing to pursue 
- his central claim is that XML needs a database behind it! After quoting 
the introduction to XML 1.0, with the outline of goals, he concludes:

http://searchdatabase.techtarget.com/tip/1,289483,sid13_gci511729,00.html

>What the authors are talking about here is nothing but database 
>management. And, in fact, telling "what things are, how they are related 
>and how to deal with them" is the very function of a data model, a theory 
>of data that conveys semantics--what data means--to the DBMS, such that it 
>can "take orders, transmit medical records, even run factories and 
>scientific instruments" from users via applications.
>
>Even leaving the very important issue of what data model, if any, 
>underlies XML, note very carefully: in a database environment, the meaning 
>(conveyed by any data model) is declared (by database designers) to the 
>DBMS. It is the DBMS that has this knowledge and manages data accordingly, 
>on behalf of user applications (integrity enforcement, data manipulation, 
>physical retrievals/updates and optimization, etc.). Indeed, the whole 
>point of database management is to centralize these functions in the DBMS, 
>away from file-processing application programs, because the latter are not 
>cost-effective.

If the real schema is that of the XML, we need databases with knowledge of 
that schema, and query languages that can manage data accordingly.

Of course, Fabian would then go on to say that the only sound kind of DBMS 
is a relational database, but I hope we can feel free to differ with him on 
that.

Jonathan