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Re: OODBMS papers needed
On Tue, 21 Dec 1999, Christophe Vigny wrote:
> >%_in fact it is a bit difficult for an sql programmer like me to understand how I can
> get benefit from ozone. as usualy I think in sql.
> Can we querry an ozone db with a langage like oql or Xpath.
OQL: no! I would not suggest using OQL. It's not SQL but it's also not OO. You
get all the disadvantages of both but no advantages.
Again: In my eyes, the programming of transient and persistent objects in
an OODBMS should not differ or it should differ only where absolutely needed.
But using OQL means to use different languages (OQL and Java) for transient and
persistent objects and this leads to the impedance mismatch which we want to
avoid with ozone.
Yes, there are reasons why it could be a good idea to use a special query
language. But these reasons are valid only if the underlying data, their types
and such things are strongly defined.
XPath: yes. There is a persistent implementation of DOM included in the ozone
distribution. This allows you to store XML/DOM in ozone and query via XPath.
But today, this is possible for "native" XML data only. It is not yet possible
to query other than DOM objects in the database via XPath. But we plan to use
BML or KBML (bean markup languages) to make all database content available for
searching via XML tools such as XPath.
>
> In fact I use database because of the querry langage.
What particular benefits do you get out of the combination of Java - SQL?
Falko
--
______________________________________________________________________
Falko Braeutigam mailto:falko@softwarebuero.de
softwarebuero m&b (SMB) http://www.softwarebuero.de