XML to table. Trouble with example from documentation

Question

I read documentation "Oracle9i Application Developer's Guide - XML"
(Release 1 (9.0.1),Part Number A88894-01)
5. Database Support for XML
TABLE Functions
Table Functions Example 1: Exploding the PO to Store in a Relational Table
I try run this example in SQL*Plus WorkSheet
1. I type
create type poRow_type as object
poname varchar2(20),
postreet varchar2(20),
pocity varchar2(20),
postate char(2),
pozip char(10)
--ok
2. I type
create type poRow_list as TABLE of poRow_type;
--ok
3. I type
create function poExplode_func (arg IN sys.XMLType) return poRow_list
pipelined is
out_rec poRow_type;
poxml sys.XMLType;
i binary_integer := 1;
argnew sys.XMLType := arg;
begin
loop
-- extract the i'th purchase order!
poxml := argnew.extract('//PO['||i||']');
exit when poxml is null;
-- extract the required attributes..!!!
out_rec.poname := poxml.extract('/PONAME/text()').getStringVal();
out_rec.postreet := poxml.extract('/POADDR/STREET/text()').getStringVal();
out_rec.pocity := poxml.extract('/POADDR/CITY/text()').getStringVal();
out_rec.postate := poxml.extract('/POADDR/STATE/text()').getStringVal();
out_rec.pozip := poxml.extract('/POADDR/ZIP/text()').getStringVal();
PIPE ROW(out_rec);
i := i + 1;
end loop;
return;
end;
-- ok
4. And I type
select *
from TABLE( CAST(
poExplode_func(
sys.XMLType.createXML(
'<?xml version="1.0"?>
<POLIST>
<PO>
<PONAME>Po_1</PONAME>
<POADDR>
<STREET>100 Main Street</STREET>
<CITY>Sunnyvale</CITY>
<STATE>CA</STATE>
<ZIP>94086</ZIP>
</POADDR>
</PO>
<PO>
<PONAME>Po_2</PONAME>
<POADDR>
<STREET>200 First Street</STREET>
<CITY>Oaksdale</CITY>
<STATE>CA</STATE>
<ZIP>95043</ZIP>
</POADDR>
</PO>
</POLIST>')
) AS poRow_list));
-- ERROR
poExplode_func(
error in line 3:
ORA-30625: method dispatch on NULL SELF argument is disallowed
ORA-06512: at "ITZ.POEXPLODE_FUNC", line 16
ORA-06512: at line 1
Why error ? What can I do ?
Thanks

Answer 1

I read documentation "Oracle9i Application Developer's Guide - XML"
(Release 1 (9.0.1),Part Number A88894-01)
5. Database Support for XML
TABLE Functions
Table Functions Example 1: Exploding the PO to Store in a Relational Table
I try run this example in SQL*Plus WorkSheet
1. I type
create type poRow_type as object
poname varchar2(20),
postreet varchar2(20),
pocity varchar2(20),
postate char(2),
pozip char(10)
--ok
2. I type
create type poRow_list as TABLE of poRow_type;
--ok
3. I type
create function poExplode_func (arg IN sys.XMLType) return poRow_list
pipelined is
out_rec poRow_type;
poxml sys.XMLType;
i binary_integer := 1;
argnew sys.XMLType := arg;
begin
loop
-- extract the i'th purchase order!
poxml := argnew.extract('//PO['||i||']');
exit when poxml is null;
-- extract the required attributes..!!!
out_rec.poname := poxml.extract('/PONAME/text()').getStringVal();
out_rec.postreet := poxml.extract('/POADDR/STREET/text()').getStringVal();
out_rec.pocity := poxml.extract('/POADDR/CITY/text()').getStringVal();
out_rec.postate := poxml.extract('/POADDR/STATE/text()').getStringVal();
out_rec.pozip := poxml.extract('/POADDR/ZIP/text()').getStringVal();
PIPE ROW(out_rec);
i := i + 1;
end loop;
return;
end;
-- ok
4. And I type
select *
from TABLE( CAST(
poExplode_func(
sys.XMLType.createXML(
'<?xml version="1.0"?>
<POLIST>
<PO>
<PONAME>Po_1</PONAME>
<POADDR>
<STREET>100 Main Street</STREET>
<CITY>Sunnyvale</CITY>
<STATE>CA</STATE>
<ZIP>94086</ZIP>
</POADDR>
</PO>
<PO>
<PONAME>Po_2</PONAME>
<POADDR>
<STREET>200 First Street</STREET>
<CITY>Oaksdale</CITY>
<STATE>CA</STATE>
<ZIP>95043</ZIP>
</POADDR>
</PO>
</POLIST>')
) AS poRow_list));
-- ERROR
poExplode_func(
error in line 3:
ORA-30625: method dispatch on NULL SELF argument is disallowed
ORA-06512: at "ITZ.POEXPLODE_FUNC", line 16
ORA-06512: at line 1
Why error ? What can I do ?
Thanks