How to retrieve a part of XML document

Question

Dear Everyone
I am using
Oracle: Berkeley DB XML 2.4.16: (October 21, 2008)
Berkeley DB 4.6.21: (September 27, 2007)
with python api on mac OSX.
I want to copy a part of XML document within the document.
For example, assume that we have the following XML in dbxml.
<A>
<B id="1">
<C>hello</C>
<D>hi</D>
</B>
</A>
I want to copy <B> with different "id" like,
<A>
<B id="1">
<C>hello</C>
<D>hi</D>
</B>
<B id="2">
<C>hello</C>
<D>hi</D>
</B>
</A>
How can I do this?
One more question. I want to retrieve a part of XML as string.
For example,
I want to have a string ' <B id="1"><C>hello</C><D>hi</D></B>'
How can I do this?
Thank you very much for your kind help in advance.
Best regards,
-Yoshi

Answer 1

Hi,
I couldn't add a document like you described:
dbxml
dbxml> createC test.dbxml
dbxml> putD "mydoc" "<C>hello</C><D>hi</D>" "s"
stdin:5: putDocument failed, Error: Error: XML Indexer: Fatal Parse error in document at line 1, char 13. Parser message: Expected comment or processing instruction (Document: mydoc)
but, if I fix it and make it well formed it worked, so for
the experiment I did that:
dbxml> putD "mydoc" "<mydoc><C>hello</C><D>hi</D></mydoc>" "s"
Document added, name = mydoc
I could have added as two separate documents, document 1: <C>hello</C>,
document 2: <D>hi</D>, but, I don't know what you are trying to do, so
I'll stick with this example to the first.
Then I ran a query to show what you did:
dbxml> query 'collection("test.dbxml")/mydoc/*'
2 objects returned for eager expression 'collection("test.dbxml")/mydoc/*'
dbxml> print
<C>hello</C>
<D>hi</D>
I can do the same thing using a query that returns something:
dbxml> query 'for $i in collection("test.dbxml")/mydoc/* return $i'
2 objects returned for eager expression 'for $i in collection("test.dbxml")/mydoc/* return $i'
dbxml> print
<C>hello</C>
<D>hi</D>
This duplicates, but the wrong way:
dbxml> query 'for $i in collection("test.dbxml")/mydoc/* return ($i,$i)'
4 objects returned for eager expression 'for $i in collection("test.dbxml")/mydoc/* return ($i,$i)'
dbxml> print
<C>hello</C>
<C>hello</C>
<D>hi</D>
<D>hi</D>
dbxml> query 'for $j in (1,2) for $i in collection("test.dbxml")/mydoc/* return $i'
4 objects returned for eager expression 'for $j in (1,2) for $i in collection("test.dbxml")/mydoc/* return $i'
dbxml> print
<C>hello</C>
<D>hi</D>
<C>hello</C>
<D>hi</D>
And, finally, for your last string example:
dbxml> query 'for $i in collection("test.dbxml")/mydoc/C for $j in collection("test.dbxml")/mydoc/D return concat("<C>",$i,"</C>", "<D>", $j, "</D>")'
1 objects returned for eager expression 'for $i in collection("test.dbxml")/mydoc/C for $j in collection("test.dbxml")/mydoc/D return concat("<C>",$i,"</C>", "<D>", $j, "</D>")'
dbxml> print
<C>hello</C><D>hi</D>
I don't get the 'id' change though.
I hope this helps.
-g