Extract element value from a trigger

Question

Hi,
I would like to create an 'before/after insert' trigger on a XMLType table that
would extract a value of an element of the inserted XML.
However, I created the following trigger but failed with error :
SQL> create or replace trigger trig_po
2 after insert on purchaseorder
3 for each row
4 declare
5 v_ref varchar2(30);
6
7 begin
8 v_ref := :NEW.extractvalue('/PurchaseOrder/Reference');
9
Warning: Trigger created with compilation errors.
SQL> show error
Errors for TRIGGER TRIG_PO:
LINE/COL ERROR
5/12 PLS-00049: bad bind variable 'NEW.EXTRACTVALUE'
SQL>
The XMLType table is created as follow :
BEGIN
DBMS_XMLSCHEMA.registerSchema(
SCHEMAURL => 'http://localhost:8080/swd/XSD/purchaseOrder.xsd',
SCHEMADOC => xdbURIType('/swd/XSD/purchaseOrder.xsd').getClob(),
LOCAL => FALSE,
GENTYPES => TRUE,
GENTABLES => TRUE);
END;
And, the following SQL can successfully insert a XML into this XMLType table
without any trigger implemented.
insert into purchaseorder values (xmltype(
'<?xml version="1.0" encoding="US-ASCII"?>
<PurchaseOrder xsi:noNamespaceSchemaLocation="http://localhost:8080/swd/XSD/purchaseOrder.xsd"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xdb="http://xmlns.oracle.com/xdb">
<Reference>ADAMS-20011127121052815PST</Reference>
<Actions>
<Action>
<User>SCOTT</User>
</Action>
</Actions>
<Reject/>
<Requestor>Julie P. Adams</Requestor>
<User>ADAMS</User>
<CostCenter>R20</CostCenter>
<ShippingInstructions>
<name>Julie P. Adams</name>
<address>300 Oracle Parkway
Redwood Shores
CA
94065
USA</address>
<telephone>650 506 7300</telephone>
</ShippingInstructions>
<SpecialInstructions>Ground</SpecialInstructions>
</PurchaseOrder>'))
Thanks in advanced.

Answer 1

ExtractValue is a SQL Function not a method
You'll need something along the lines of
select extractValue(:new.sys_nc_rowinfo$,'/PurchaseOrder/Reference')
  into v_ref
  from dual;