Problem with xs:integer (I think)

Question

Hi,
Firstly, I'm using Oracle database version 11.2.0.1.0
The overall task is to absorb data from an XML file and create records in a single destination table.
I've studied the excellent thread at Load xml data in Oracle table
and copied and hacked Odie's examples.
I've got something to work, but there's just that one final problem, explained so.
To test out my code, I wrapped the "select" that gets the data from the XML file into a cursor For loop, and inside
the loop body I just use dbms_output so I can see that the values are being processed okay. This works a treat, so my
final task was to abandon the cursor For loop and instead make the select statement the source of data for an Insert
statement. This is where my plans become unstuck.
In order to cater for duplicate rows, I'm using the "at" bit of the "for" loop as so: "for $i at $bibnum in /collection/record".
That bit of data (available through the variable "$bibnum") when printed out via the older dbms_output code did show
a pleasing consecutive sequence of digits. But try and insert this into a plain database table and all I get is nulls. Yuk.
Trying to read around this, I've managed through dubious means to glean that the variable is of type "xs:integer". It seems converting
this to a oracle "number" type is problematic. There is mention on the web page http://docs.oracle.com/cd/E14571_01/doc.1111/e15867/app_xquery_sql_reference.htm
about conversion from "number" to "xs:integer", hence I am presuming that the converse also holds.
But the blooming thing still doesn't work.
Other numbers from the select statement populate into my destination table fine. It's just the xs:integer that's the issue.
I've tried changing the "columns" part of the xmltable call and used "number", "number(8)", "number(8,0)" and other variants. No joy.
I've also tried changing the column type of the target table. Still no joy.
I've tried converting the xs:integer to a xs:decimal, and then use that. Still nothing.
Time to throw myself on the mercy of the forum. Any easy way to convert the xs:integer into a plain string?
If there is no obvious answer, I will throw together a small self-contained piece of example code and come back here.
Any help appreciated; thanks in advance.
Mungo (newbie with xmltables - probably going round the "long" way on this task :-)

Answer 1

That's a funny one, SELECT is working but INSERT is not...
I guess it's an issue with the CBO and XQuery optimization.
If you're always using a variable as your XML source, you can disable it by adding the NO_XML_QUERY_REWRITE hint. It should solve the problem :
SQL> create table raw_bib (
  2    recordID    number
  3  , datafieldID number
  4  , tag         number
  5  , subfield    varchar2(10)
  6  , val         varchar2(4000)
  7  )
  8  ;
Table created
SQL> var xml_data varchar2(4000)
SQL>
SQL> begin
  2   :xml_data := '<collection>
  3   <record>
  4    <datafield tag="1">
  5     <subfield code="1d1s1">ABC</subfield>
  6     <subfield code="1d1s2">DEF</subfield>
  7     <subfield code="1d1s3">GHI</subfield>
  8    </datafield>
  9    <datafield tag="2">
10     <subfield code="1d2s1">ABC</subfield>
11     <subfield code="1d2s2">DEF</subfield>
12     <subfield code="1d2s3">GHI</subfield>
13    </datafield>
14   </record>
15   <record>
16    <datafield tag="1">
17     <subfield code="2d1s1">ABC</subfield>
18     <subfield code="2d1s2">DEF</subfield>
19     <subfield code="2d1s3">GHI</subfield>
20    </datafield>
21   </record>
22  </collection>';
23  end;
24  /
PL/SQL procedure successfully completed
SQL>
SQL> insert into raw_bib(recordID, datafieldID, tag, subfield, val)
  2  select /*+ no_xml_query_rewrite */
  3         recordID, datafieldID, tag, subfield, val
  4  from xmltable(
  5   'for $i at $bibnum in /collection/record
  6   return
  7   for $j at $dfnum in  $i/datafield
  8   return
  9   for $k in $j/subfield
10     return element r {
11      element finalData {data($k)}
12      , element datafieldtag {data($j/@tag) }
13      , element subfieldcode { data($k/@code) }
14      , element whichdatafield {data($dfnum)}
15      , element bibnumber { $bibnum }
16      }
17    '
18  passing xmltype(:xml_data)
19  columns recordID    number         path 'bibnumber'
20        , datafieldID number         path 'whichdatafield'
21        , tag         number         path 'datafieldtag'
22        , subfield    varchar2(10)   path 'subfieldcode'
23        , val         varchar2(4000) path 'finalData'
24  )
25  ;
9 rows inserted
SQL> select * from raw_bib;
  RECORDID DATAFIELDID        TAG SUBFIELD   VAL
         1           1          1 1d1s1      ABC
         1           1          1 1d1s2      DEF
         1           1          1 1d1s3      GHI
         1           2          2 1d2s1      ABC
         1           2          2 1d2s2      DEF
         1           2          2 1d2s3      GHI
         2           1          1 2d1s1      ABC
         2           1          1 2d1s2      DEF
         2           1          1 2d1s3      GHI
9 rows selected