[xquery-talk] How do I insert a node as first element within a for loop?

[Ghislain Fourny]

Hi Alex,

Me again. I read through your expected result too fast and missed the b4
part :-)

So indeed you need a copy modify:

...
let $fields :=
<form13FFile>
{
for $c in $data
return
  copy $new-node := $c
  modify insert nodes <b4>test</b4> as first into $new-node
  return $new-node
}
</form13FFile>
...

I hope I got it right this time!

Kind regards,
Ghislain


On Wed, Jul 6, 2016 at 11:19 AM, Ghislain Fourny <g at 28.io> wrote:
>
> Hi Alex,
>
> You can either use a query, or updates. Your query mixes both, which is
why you are getting an error, as updates can't be nested in expressions
that produce items.
>
> In your case though, since you need to modify the top-level, a query
makes most sense, and the good news is it's really simple.
>
> ...
> let $fields :=
> <form13FFile>{
>   $data
> }</form13FFile>
> ...
>
> Then you can replace the file with the results of the query as you do
with file:write.
>
> If you really want to update, you can do something like:
>
> replace node $data with
>   <form13FFile>{
>     $data
>   }</form13FFile>
>
> but then you can't use the file:write machinery and need to rely on the
underlying engine to do the edit in place.
>
> In the more general case where you need to edit plenty of places in your
document, you can use the copy-modify-return expression. It's very handy to
create an updated copy.
>
> I hope it helps!
>
> Kind regards,
> Ghislain
>
>
>
> On Wed, Jul 6, 2016 at 11:10 AM, Alex Muir <alex.g.muir at gmail.com> wrote:
> >
> >
> > Greetings,
> >
> > Running in Basex I get the following error:
> >
> > XUST0001 element constructor: no updating expression allowed.
> >
> > When trying to insert insert nodes test as first into $c
> >
> > I feel like my code is following the examples I see online although
clearly I've got something wrong.
> >
> > How do I insert a node with a for loop?
> >
> > declare namespace db="http://basex.org/modules/db";
> > declare namespace file="http://expath.org/ns/file";
> > declare variable $form13FFileNumber as xs:string external;
> >
> > let $data :=
db:open('13F')//data[contains(edgarSubmission/formData/coverPage/form13FFileNumber,$form13FFileNumber)]
> >
> > let $fields :=
> >
> > <form13FFile>
> > {
> > for $c in $data return
> > insert nodes <b4>test</b4> as first into $c
> > }
> > </form13FFile>
> >
> > return file:write(concat('../OUT/' , $form13FFileNumber , '.xml'),
$fields)
> >
> > To be more clear my xml looks something like
> >
> >    <data>
> >      <first_Child>text</first_child>
> >    </data>
> >    <data>
> >      <first_Child>text</first_child>
> >    </data>
> >
> > and I would like it to adjust to
> >
> > <form13FFile>
> >     <data>
> >      <b4>test</b4>
> >      <first_Child>text</first_child>
> >     </data>
> >     <data>
> >      <b4>test</b4>
> >      <first_Child>text</first_child>
> >     </data>
> > </form13FFile>
> >
> >
> >
> > Regards
> > Alex
> > tech.jahtoe.com
> > bafila.jahtoe.com
> >
> > _______________________________________________
> > talk at x-query.com
> > http://x-query.com/mailman/listinfo/talk
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