Insert update attribute

[apb2006]

I am trying to use mxquery 0.6 to update an attribute or insert it if not there.

My db.xml file is like this
-----------
<?xml version='1.0' encoding='UTF-8' ?>
<db>
   <rec key="1">Apple</rec>
   <rec key="2" timestamp="2009-06-01T15:34:27.857Z">BB</rec>
   <rec key="3">orange</rec>
   <rec key="4" fred="2009-06-01T15:34:27.857Z">DD</rec>
</db>
-----------
My Xquery is
------------------
(: xquery update test: update or insert timestamps  :)
declare updating function
   local:upsert($e as element(),
          $an as xs:QName,
          $av as xs:anyAtomicType)
   {
   let $ea := $e/attribute()[fn:node-name(.) = $an]
   return
   
      if (fn:empty($ea))
      then insert node attribute {$an} {$av} into $e
      else replace value of node $ea with $av
    
   };

let $db:=doc("db.xml")

for $r in $db//rec
return  local:upsert($r,timestamp,current-time())
-----------------------

I am getting a Context item not set error. Is this due to my lack of understanding or is it a mxquery issue?

/Andy

[apb2006]

I think I have got it, using QName works :-)

local:upsert($r,QName("","timestamp"),current-time())

[Peter M. Fischer]

Maybe a little bit of clarification:

local:upsert($r,timestamp,current-time()) is actually

local:upsert($r,./timestamp,current-time()),

since timestamp is a child location step instead of string.

In the absence of Schema information, it cannot be determined statically that this location step will not produce a QName (or something that can be cast into a QName)

Hope that helps,

Peter

[apb2006]

Thanks, I spent a long time going round in circles with this. I expected this to work...

upsertAttribute($r,"timestamp",current-time())

but it produces a "Type not allowed" error - no doubt correctly, so I removed the quotes in desperation.

After I sent the message I realised that this was an xpath with no "context".

Are you saying the .."timestamp".. form could be made to work in the presense of suitable Schema information?  

Andy

[Peter M. Fischer]

No, the timestamp (path expression) case could be analyzed better with schema knowledge and static typing to show that there will be an error.

Just a quick hint: I don't know which editor you are using to write XQuery. The problem of using a path expression instead of a string/QName is solved nicely in XQDT, which is open source XQuery plugin for Eclipse.

Peter