[jdom-interest] rdms & jdom

Edoardo Comar edoardo at knowledgeview.co.uk
Fri Apr 6 02:13:26 PDT 2001

I was also going to store xml documents in the RDB. my xml documents will be
"data" (thrird-party and custom documents, like NewsML), "rules" (complex
user objects described in XML) and lots of XSLT stylesheets (used by the
rule objects).

my concern was that storing xml on the RDB, I lose the ability of easily
referring from one xml doc to another via relative URIs.
for example:
a rule element can contain an attribute  stylesheet="util/mystyle.xsl"
a stylesheet is likely to use <xsl:import> and the document() function

"navigation" via reltive URIs is straightforward if everything is stored on
the file system.
how can it be done simply if we use an RDB ?


> -----Original Message-----
> From: jdom-interest-admin at jdom.org
> [mailto:jdom-interest-admin at jdom.org]On Behalf Of
> philip.nelson at omniresources.com
> Sent: 06 April 2001 03:40
> To: jdom-interest at jdom.org
> Subject: RE: [jdom-interest] rdms & jdom
> > I want to know which is the best way to store xml for jdom.
> > My working plan
> > has always been to store xml as a clob and deliver up the
> > jdom document as
> > needed. We could also serialize the jdom object as a blob. The second
> > approach shortens the response time on delivering the jdom
> > object...but
> > increases the storage requirements on the database.
> >
> > A third approach is to map the jdom object into the rdms.
> Though this list has been quiet, it seems people have pretty
> strong feelings
> about this issue.  There are very reasonable reasons to do this IMHO and
> some problems I ran into that I can share.
> Positive
> - In any load balanced scenario, the file system won't do.
> - clob/blob is conceptually very simple
> - you get to avoid long fruitless normalization discussions with insane
> dba's :^)
> - versioning is simpler though not simple
> - simple transaction model depending on the DB
> Negatives
> - I had a rotten time with clobs in Oracle 8i.  Major data corrupting bugs
> actually.  Your mileage may vary.
> - you may still have to map some of the fields
> - database queries are not straightforward at all.
> - query tools often cannot deal with clobs
> - *very* database dependent implementations and you are usually
> on your own
> for help
> - your dba may not speak to you again
> You have missed option 4, a shared file system with database tracking.
> Oracle has a system like this already but I don't have any personal
> experience with it.  Mapping is good if you don't have lots of different
> document types or don't have to change your document versions very often.
> Better check your performance parameters if you go the clob route because
> it's not easy to upgrade your database compared to other parts of the
> system.
> _______________________________________________
> To control your jdom-interest membership:
> http://lists.denveronline.net/mailman/options/jdom-interest/yourad
dr at yourhost.com

More information about the jdom-interest mailing list