Dynamic XPath in XQuery or XQSE

Question

Is there a way to execute dynamic xpath expression in XQuery or XQSE, to do something like:
declare xqse function tns:checkName($addrBook as element(),$name as xs:String ) as xs:boolean {
declare $var as xs:String := "Address/Person[@name='" + $name +"']";
( : test if expression in $var returns not empty result when applied to $addrBook : )
return value( $resultOfEvaluation) ;
Thank You
Edited by [email protected] at 03/13/2008 7:19 PM
Edited by [email protected] at 03/13/2008 7:19 PM
Edited by [email protected] at 03/13/2008 7:20 PM

Answer 1

You haven't described why you want to do this - I suspect it is might be unnecessary/over-kill. Anyway
1) in the interest of efficiency, DSP compiles and optimizes xquery, and therefore the xquery cannot be modified at run-time.
2) the Filter api will let you apply filters, which effectively generate a new query, compile it and execute it. But you can only apply selections to elements that are exposed in the result
The thing is that final client should not use mediator api, and i do not want to have an intermediate client that would use mediator. I don't understand what you mean here - how is the client supposed to to submit a response to DSP and get a result if it does not call DSP directly or indirectly?
If the client already has the result, and you want to find something within that result, by far the most efficient way (aside from only returning that result in the xquery submitted to DSP), is to navigate through the DataObject with the get() methods. Firing up an xquery engine is a very expensive way to go through a DataObject - to do this you will need to serialize the DataObject into xml, create an XmlObject from that string, and then evaluate the xquery.