XML parser error; when XPath elements starts with "_"

Question

Hi,
I have a problem in extracting elements from XML which is starting with "_". please check the queries below executed on Oracle 10g.
Query 1:
SELECT EXTRACTVALUE(XMLTYPE('<A><_B>1</_B><_C>2</_C><_D>3</_D><E>4</E></A>'),'/A/_B') FROM DUAL;
Error starting at line 1 in command:
SELECT EXTRACTVALUE(XMLTYPE('<A><_B>1</_B><_C>2</_C><_D>3</_D><E>4</E></A>'),'/A/_B') FROM DUAL
Error report:
SQL Error: ORA-31011: XML parsing failed
ORA-19202: Error occurred in XML processing
LPX-00601: Invalid token in: '/A/_B'
31011. 00000 - "XML parsing failed"
*Cause:    XML parser returned an error while trying to parse the document.
*Action:   Check if the document to be parsed is valid.
Query 2:
SELECT EXTRACTVALUE(XMLTYPE('<A><_B>1</_B><_C>2</_C><_D>3</_D><E>4</E></A>'),'/A/E') FROM DUAL;
EXTRACTVALUE(XMLTYPE('<A><_B>1</_B><_C>2</_C><_D>3</_D><E>4</E></A>'),'/A/E')
4
Oracle version:
BANNER
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Prod
PL/SQL Release 10.2.0.1.0 - Production
CORE     10.2.0.1.0     Production
TNS for 32-bit Windows: Version 10.2.0.1.0 - Production
NLSRTL Version 10.2.0.1.0 - Production
Please let me know if there is any workaround for this.*
Thanks,
Veerababu Kanumilli.

Answer 1

Hi MichaelS,
- I have executed the queries provided by you, but I am not able to get the result in 10g when I am trying to access elements with "_" in XPath.
select * from v$version where rownum = 1;
select extractvalue (xmltype ('&lt;A&gt;<_B>1</_B><_C>2</_C><_D>3</_D><E>4</E>&lt;/A&gt;'), '/A/_B') "_B" from dual;
select extractvalue (xmltype ('&lt;A&gt;<_B>1</_B><_C>2</_C><_D>3</_D><E>4</E>&lt;/A&gt;'), '/A/E') "E" from dual;
Output:
BANNER
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Prod
Error starting at line 4 in command:
select extractvalue (xmltype ('&lt;A&gt;<_B>1</_B><_C>2</_C><_D>3</_D><E>4</E>&lt;/A&gt;'), '/A/_B') "_B" from dual
Error report:
SQL Error: ORA-31011: XML parsing failed
ORA-19202: Error occurred in XML processing
LPX-00601: Invalid token in: '/A/_B'
31011. 00000 - "XML parsing failed"
*Cause:    XML parser returned an error while trying to parse the document.
*Action:   Check if the document to be parsed is valid.
E
4
Thanks,
Veerababu Kanumilli