[xquery-talk] last possible child's attribute
michalmas at gmail.com
Sun Mar 8 14:45:34 PST 2009
It still gives me the same error:
XQuery Serialization Error!
> A document node may not have an attribute node or a namespace node as a
Yes, i meant last possible node that has a value for given attribute.
On Sun, Mar 8, 2009 at 2:32 PM, G. Ken Holman <gkholman at cranesoftwrights.com
> At 2009-03-08 13:43 +0100, Michalmas wrote:
>> What i need to get in xquery is the last possible child's attribute.
> It looks to me like you need the last possible descendant's attribute, not
> Let's say i have following XML:
>> <aa lc=1>
>> <aaa lc=00>
>> <bb lc=0>
>> <zz lc=1>
>> <ccc lc=123>
>> and i want to get the last child of 'a' node. So, in this case, it would
>> be node 'ccc'. Then, i want to get lc attribute - in this example, 123.
> Two ways you could express it, based on how easy you think each will be
> maintained by someone reading your code:
> To be explicit, you want the attribute of the last descendant of the
> To be concise, you want the last attribute descending from the element:
> The code below shows both of those working ... and I doubt there would be
> any difference in execution time ... choose whichever one "reads" better
> from a maintenance perspective.
> I believe maintenance of transforms is as important as performance ... let
> the processor worry about the optimization of the performance.
> BTW, I'm assuming you know the attribute's name. There is no such concept
> as "last specified attribute" for a given element, because attributes along
> the attribute axis are in an arbitrary order, they are not in specified
> order. I find many students assume that just because they specified
> attributes in a particular order they are going to find them in that order
> when they walk the attribute axis. XML says that attributes are unordered.
> In the data model, they have an order, you just don't know what that order
> is. So you can reliably walk over an attribute axis multiple times in one
> transformation and get the attributes in the same order each time during
> that transformation, but they won't necessarily be in that order the next
> time or with another processor.
> I hope this helps.
> . . . . . . . . . . Ken
> t:\ftemp>type michalmas.xml
> <aa lc="1">
> <aaa lc="00">
> <bb lc="0">
> <zz lc="1">
> <ccc lc="123">
> t:\ftemp>type michalmas.xq
> string( a/descendant::*[last()]/@lc ),
> string( (a//@lc)[last()] )
> t:\ftemp>xquery michalmas.xml michalmas.xq
> <?xml version="1.0" encoding="UTF-8"?>123 123
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