RE: a message for the SapDB visionnaire in chief

Hi Max,

I'm afraid there is some kind of misunderstanding. There is no such feature as a XPATH querying, not even a hidden one.
Yes we do use XPATH, but it is only used for indexing purposes. With XPATH expressions you describe which values you want to extract from the XML documents. Then these values are stored as WebDAV properties for the document. Querying of indexed documents is a mere SELECT ... FROM WEBDAV_PROPERTY table. Not much XPATH involved there, in fact: nothing!
The XML documents itself are stored as ordinary BLOBs. No way querying them besides the index values stored in WEBDAV_PROPERTY.
However, if you need to use those index values for one of your applications you could select them with ordinary SQL from WEBDAV_PROPERTY. With that you would find the related file in WEBDAV_INODE and so on. Just have a look at the WebDAV schema. (Tables start with "WEBDAV_"). Anyway you SHOULD NOT change any WebDAV data unless you are absolutely sure what you are doing and not destroying any important stuff. Your WebDAV might not appreciate this :o)

So XPATH for us is a means for modelling the indexing and nothing else. Everything that could possibly exposed there, is exposed allready.

By now (and in the predictable future) there are no plans to provide a XPATH/XQuery/XUpdate feature for that WebDAV implementation.
Anyway the XPATH/XQuery/XUpdate stuff is on our minds. But no features or timelines are set by now (and in the predictable future).

Hope this clarifies the issue. If not, feel free to contact me again.

Cheers,
Daniel


-----Original Message-----
From: Max [mailto:[email protected]]
Sent: Dienstag, 19. August 2003 19:25
To: [email protected]
Subject: a message for the SapDB visionnaire in chief



   I was looking at SapDB's source code and it seemed
as if there was an effort at supporting XML storing, quering, and
indexing capabilities at some point. From what I understand
the goal of this was to supply a back end for WebDAV capabilities.

   Now, the suggestion : How about exposing the XPath querying
(it seems to be there already, just a hidden feature), and
adding something like XUpdate for updating ?

  There is a similar project going on with postgres :

  http://gborg.postgresql.org/project/xpsql/projdisplay.php

  And of course Oracle and DB2 have it in the form of SQL extensions
where one can put an xpath expression in a where clause, etc...

  As a first step, just exposing the existing XML 
storing/querying/indexing capabilities would seem like an
easy enough thing to do, no ?

  Another alternative could be to allow WebDAV operations to occur
withih the scope of an (sapDB) transaction, almost as good...



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