How to convert a data set into a xml data and vice versa

Question

i am new to oracle with xml..
my aim is to convert a data set into a xml data and vice versa..
my work is as follows...
my query:
select rggpk,rggcode,rggname from ms_regiongeo
to convert a data set into a xml*
select XMLType(trim(replace(dbms_xmlgen.getXML('select rggpk,rggcode, rggname from ms_regiongeo'),'<?xml version="1.0"?>',''))) XML_DATA from dual;
(this works fine and output of this query is as follows..)
<ROWSET>
<ROW>
  <RGGPK>201</RGGPK>
  <RGGCODE>Asia</RGGCODE>
  <RGGNAME>Asia</RGGNAME>
</ROW>
<ROW>
  <RGGPK>1</RGGPK>
  <RGGCODE>OTH</RGGCODE>
  <RGGNAME>Others</RGGNAME>
</ROW>
<ROW>
  <RGGPK>21</RGGPK>
  <RGGCODE>COB</RGGCODE>
  <RGGNAME>Africa and Yemen</RGGNAME>
</ROW>
<ROW>
  <RGGPK>2</RGGPK>
  <RGGCODE>AUS</RGGCODE>
  <RGGNAME>Australia</RGGNAME>
</ROW>
<ROW>
  <RGGPK>23</RGGPK>
  <RGGCODE>IND</RGGCODE>
  <RGGNAME>Indian Sub Continent</RGGNAME>
</ROW>
<ROW>
  <RGGPK>24</RGGPK>
  <RGGCODE>TVM</RGGCODE>
  <RGGNAME>North America</RGGNAME>
</ROW>
</ROWSET>
and to reverse this process, I tried a query like this..*
select EXTRACTVALUE (XML_DATA,'ROWSET/ROW/RGGPK') as EMP_ID
from(
        select XMLType(trim(replace(dbms_xmlgen.getXML('select rggpk,rggcode, rggname from ms_regiongeo'),'<?xml version="1.0"?>',''))) XML_DATA from dual
)tab1but failed.. and raised with an eror: ORA-19025
help me..
regards,
john

Answer 1

Hi-
my aim is to convert a data set into a xml data  You can refer to the below posts
Adding namespace to XML output
Re: how to convert table data in xml format based on the xsd.