Extractvalue function not recognised

Question

Hello,
I'm trying to compile a pro*c program against a 10.2.0.3.0 Oracle DB.
The precompiler does not seem to recognise the EXCTRACTVALUE function since I'm getting the following error:
Error at line 283, column 7 in file MainCheckNat.pc
EXEC SQL
......1
PLS-S-00201, identifier 'EXTRACTVALUE' must be declared
The query looks like:
EXEC SQL
SELECT COUNT(DISTINCT EXTRACTVALUE(segnalazione, '/TransactionError/TransactionReferenceNumber'))
INTO :hostvar1
FROM table
WHERE id_file = :hostvar2
I have searched the pro*c programming manual for some hints but I could not find any.
Has anybody ever met with this problem before?
Or is there anything I am doing the wrong way?
Thanks,
Massimo

Answer 1

You are right on ExtractValue. I was thinking the wrong situation. In PL/SQL you can do xmltype.extract(), but you cannot do xmltype.extractValue().
I wasn't paying close enough attention to your SQL statement but ExtractValue can return only 1 value. If it returns more, it throws and ORA-19025 error. Since you are trying to COUNT the values, you need to use Extract.
For me, the following statements run cleanly on 10.2.0.4
WITH base AS
(SELECT XMLTYPE('<TransactionError><TransactionReferenceNumber>1</TransactionReferenceNumber></TransactionError>') segnalazione FROM dual)
SELECT EXTRACTVALUE(segnalazione, '/TransactionError/TransactionReferenceNumber') try1,
       EXTRACT(segnalazione, '/TransactionError/TransactionReferenceNumber/text()').getstringval() try2,
       COUNT(DISTINCT EXTRACT(segnalazione, '/TransactionError/TransactionReferenceNumber/text()').getstringval()) try3
  FROM base;
TRY1     TRY2     TRY3
1     1     1When you have multiple Ref Numbers, you get this instead of what you were expecting
WITH base AS
(SELECT XMLTYPE('<TransactionError><TransactionReferenceNumber>1</TransactionReferenceNumber><TransactionReferenceNumber>2</TransactionReferenceNumber></TransactionError>') segnalazione FROM dual)
SELECT EXTRACT(segnalazione, '/TransactionError/TransactionReferenceNumber/text()').getstringval() try2,
       COUNT(DISTINCT EXTRACT(segnalazione, '/TransactionError/TransactionReferenceNumber/text()').getstringval()) try3
  FROM base;
TRY2     TRY3
12     1This returns a count of the number of TransactionReferenceNumber in the XML
WITH base AS
(SELECT XMLTYPE('<TransactionError><TransactionReferenceNumber>1</TransactionReferenceNumber><TransactionReferenceNumber>2</TransactionReferenceNumber></TransactionError>') segnalazione FROM dual)
SELECT COUNT(DISTINCT t.refNumber) try3
  FROM base,
       XMLTABLE('/TransactionError/TransactionReferenceNumber'
                PASSING base.segnalazione
                COLUMNS
                refNumber   VARCHAR2(10)  PATH '.') t;
TRY3
2There is also an XQuery way to do the count but that is an area I'm still working on myself. As I said, all these run cleanly on the DB itself. If they don't work when called from your pro*C code, then I can't be of much more help as I don't know pro*C.