Dbms_xmlschema's automatic type generation

Question

Hi,
I would like to import XML documents in Oracle 9i Release 2 which contain a structure like this:
<TEST>
<TEST/>
<TEST/>
</TEST>
I am using the following schema definition:
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
elementFormDefault="qualified"
targetNamespace="http://www.informatik.hu-berlin.de/~vitt/test"
xmlns:t="http://www.informatik.hu-berlin.de/~vitt/test"
>
<xs:complexType name="C_TEST">
<xs:sequence>
<xs:element minOccurs="0" maxOccurs="unbounded" ref="t:TEST" />
</xs:sequence>
</xs:complexType>
<xs:element name="TEST" type="t:C_TEST"/>
</xs:schema>
I am importing this schema using PL/SQL's DBMS_XMLSCHEMA.registerURI with the default options, i.e. automatic type and table generation turned on. Unfortunately, this does not quite work as expected. If I ask SQL*Plus to describe the created table, Oracle disconnects:
SQL> describe TEST4711_TAB
ERROR:
ORA-03113: end-of-file on communication channel
Describing the created types shows that something went wrong:
SQL> describe C_TEST4710_T
C_TEST4710_T is NOT FINAL
Name Null? Type
SYS_XDBPD$ XDB.XDB$RAW_LIST_T
TEST REF OF XMLTYPE
SQL> describe TEST4712_COLL
TEST4712_COLL VARRAY(2147483647) OF C_TEST4710_T
TEST4712_COLL is NOT FINAL
Name Null? Type
SYS_XDBPD$ XDB.XDB$RAW_LIST_T
TEST REF OF XMLTYPE
As far as I understand, the TEST element of C_TEST4710_T should be of the TEST4712_COLL type, not simply a REF OF XMLTYPE, as there may be more than one TEST XML elements inside a TEST element.
How can I get around this problem?
TIA,
Thorsten

Answer 1

Hi,
What version of Oracle are you using?9.2.0.1.0
Have you looked at your server to see if the Oracle
instance is creating any trace or dump files?The DESCRIBE command mentioned in my original post results in the following written to the alert_lehre.log file:
Mon Aug 30 16:59:57 2004
Errors in file /oracle/lehre/admin/lehre/udump/lehre_ora_7673.trc:
ORA-07445: exception encountered: core dump [qmtAddProperty()+783] [SIGSEGV] [Address not mapped to object] [0x29] [] []
Currently, I do not have access to the trace file, though.
Have you tried a different version of SQLplus just to
see if it does the describe?No. However, I get the same error (and the same alert.log entry) when I try to insert a sample XML file into the table, as well from SQLplus as from a third-party tool using OCI.
I seem to have found a workaround now -- a slight reformulation of the XML Schema definition appears to make Oracle create a correct type definition:
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
elementFormDefault="qualified"
targetNamespace="http://www.informatik.hu-berlin.de/~vitt/test"
xmlns:t="http://www.informatik.hu-berlin.de/~vitt/test"
>
<xs:complexType name="C_TEST">
<xs:sequence>
<!-- old: <xs:element minOccurs="0" maxOccurs="unbounded" ref="t:TEST" /> -->
<xs:element minOccurs="0" maxOccurs="unbounded" name="TEST" type="t:C_TEST"/>
</xs:sequence>
</xs:complexType>
<xs:element name="TEST" type="t:C_TEST"/>
</xs:schema>
SQL> describe C_TEST6847_T;
C_TEST6847_T is NOT FINAL
Name Null? Type
SYS_XDBPD$ XDB.XDB$RAW_LIST_T
TEST XDB.XDB$XMLTYPE_REF_LIST_T
-- Thorsten