Jonathan Borden wrote:

More thoughts.

> The XUpdate spec and DTD is looking good.

Why a DTD and not a Schema?  Just curious.

>   the one thing i would like to see is an
> <xupdate:update-or-insert select="..">
>   alternatively we can also include an
> <xupdate:choose><xupdate:when ...>..<xupdate:otherwise..>
> construct.

This all seems very document-centric to me.  Database operations are
typically performed on sets of objects, not single objects, and they
only become single objects when the participating data sets are narrowed
into a single object through criteria.  A database that can't perform
set operations with a single call is of little use to anyone.  The
reason why relational databases are so powerful is because I can
conditionally update or delete a million records with a single line of
SQL.    I dunno, maybe I misread something here.

> Also, the remainind construct in XEditor which I find useful is the
> "path-prefix" attribute, the reason this exists is to allow the XUpdate
> operation to take place on a specified subtree of the main document
> specified by the path-prefix value which is prepended to the generated
> XPaths (see http://www.openhealth.org/editor/editorgen.xsl for usage.
> 
> 1) this attribute is optional
> 2) when the document to be updated does have a deep hierarchy it simplifies
> the update list.
> Think of it this way: suppose the entire world is in a huge XML document,
> path-prefix allows the update operation to be carried out on a particular
> well defined location within what is otherwise a morass.

I can't buy into the argument that the world is one big XML document. 
Most XML Databases will provide functionality for pulling in XML from
non-XML data sources, and the locations of these legacy data stores,
won't fit into the XPath specification.  A path prefix can definitely
apply to a document-rooted XPath, but if you extend the notion of what
the prefix can contain into the realm of heterogenous data stores, you
can no longer encapsulate that data cleanly with an XPath.

The W3C has a lock on the document, and the XML Query Language charter
will ultimately cover document-centric querying and updating, but it
doesn't address any of our issues as developers of XML databases.  I
think our goal here is to think beyond the document into how terrabyte
repositories of XML should be managed and queried.  

--Tom

-- 
<name>Tom Bradford</name>
<title>Chief Software Architect</title>
<company>The dbXML Group</company>
<phone>(480) 421-1233</phone>
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