[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: Grand Challenge: the same query, independent of how data r
On 20 Feb 2014, at 14:43, Costello, Roger L. <costello@mitre.org> wrote: > Michael Kay wrote: > > You can encapsulate all three mechanisms > behind a function (or two functions, one for > each direction of the relationship). > > What do you mean by "function"? > > Do you mean a user-defined XPath function? Yes. For example declare function orders-for-customer($c as element(customer)) as element(order)* { return $c/order } or declare function orders-for-customer($c as element(customer)) as element(order)* { return $c/root()//order[@customer-id = $c/@id] } Michael Kay Saxonica > > How would such a user-defined function work? Would one have to provide it some indication of the relationship? For example, > > Hey function, give me the Title of the Book > written by Richard Bach, where the Title is > contained within Book (or the Title is referenced > by an intra-document link, or the Title is > referenced by a cross-document link). > > Is that what you mean? If yes, would you sketch out such a user-defined XPath function please? > > /Roger > > > -----Original Message----- > From: Michael Kay [mailto:mike@saxonica.com] > Sent: Thursday, February 20, 2014 9:30 AM > To: Costello, Roger L. > Cc: xml-dev@lists.xml.org > Subject: Re: Grand Challenge: the same query, independent of how data relationships are modeled > >> >> Fascinating! >> >> So, we want to be able to express: >> >> Give me the Title of the Book that was written by >> Richard Bach. >> >> and that should give us the correct answer, regardless of how the Book/Title relationship is modeled. >> >> Right? >> >> How do we achieve this? >> > > You can encapsulate all three mechanisms behind a function (or two functions, one for each direction of the relationship), and I would certainly recommend doing that in many cases. > > Michael Kay > Saxonica > > > _______________________________________________________________________ > > XML-DEV is a publicly archived, unmoderated list hosted by OASIS > to support XML implementation and development. To minimize > spam in the archives, you must subscribe before posting. > > [Un]Subscribe/change address: http://www.oasis-open.org/mlmanage/ > Or unsubscribe: xml-dev-unsubscribe@lists.xml.org > subscribe: xml-dev-subscribe@lists.xml.org > List archive: http://lists.xml.org/archives/xml-dev/ > List Guidelines: http://www.oasis-open.org/maillists/guidelines.php
[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] |
PURCHASE STYLUS STUDIO ONLINE TODAY!Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced! Download The World's Best XML IDE!Accelerate XML development with our award-winning XML IDE - Download a free trial today! Subscribe in XML format
|