How To Store XML Fragments Using Functions Such As XMLElement

Question

Hi
Not sure what I am missing. I wish to store XML fragments in variables so can pass around and concatenate with other fragments to make final XML document. Even before attempting to concatenate XML fragments, I am struggling to store any XML fragment in a variable. I am trying to use simple functions such as XMLElement to generate XML so can store in variable. I have seen many examples of XMLElement in SQL select statement. Can XMLElement be used in plsql? XMLElement says it returns value of type XMLType. Functions such as XMLElement make generating XML easier than creating all tags manually.
Below is simple example that demonstrates what I would like to do. I would like to be able to pass the XML fragment as either XMLType or clob. I receive error saying PLS-00201: identifier 'XMLELEMENT' must be declared
declare
vTheData XMLType;
vTheDataClob clob;
begin
  vTheData:= XMLelement("empno",'1234567');
  vTheDataClob:= xmlelement("empno",'1234567').getclobval();
end;
Where as I can use below, but surely don't have to use select into from dual method. I just expect can use XMLElement function in plsql same as sql, such as most other functions eg length, rtrim etc.
declare
vTheData XMLType;
vTheDataClob clob;
begin
  select xmlelement("empno",'1234567')
  into vTheData
  from dual;
  select xmlelement("empno",'1234567').getclobval()
  into vTheDataClob
  from dual;
end;
Hope this makes sense.
Thanks

Answer 1

Having said that, is there a more elegant way to achieve below. That is populate two XML fragments and concatenate together.
Sure, why not just only one statement?
select XMLConcat(
         XMLElement( ... )
       , XMLElement( ... )
into vTheResult
from dual;
As a second question, is it better to build and pass XML fragments as XMLType or clob?
I would say stay with XMLType but it depends on your requirement.
I generally avoid passing around pieces of data, SQL/XML functions are powerful in the way they can be used with set operations, so using them in a piecewise approach kinda negates what they're for.