Invoking Stored Function

Question

I have this function defined in my database:
create or replace FUNCTION return_string_func(x VARCHAR2) RETURN VARCHAR2
AS
BEGIN
return 'Hello ' || x;
END;
and i am trying to invoke it as follows:
PLSQLStoredProcedureCall call = new PLSQLStoredProcedureCall (); //------------------------------------A
call.setProcedureName("return_string_func");
call.addNamedArgument("x", JDBCTypes.VARCHAR_TYPE);
DataReadQuery query = new DataReadQuery ();
query.addArgument("x");
query.setCall(call);
Session session = JpaHelper.getEntityManager(em).getServerSession();
List queryArgs = new ArrayList();
queryArgs.add("venkat");
List mylist= (List)session.executeQuery(query,queryArgs);
DatabaseRecord record = (DatabaseRecord) mylist.get(0);
return (String)record.get(0); //------------------------------------B
I am getting the following error:
Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.1.3.v20110304-r9073): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: java.sql.SQLException: ORA-06550: line 5, column 3:
PLS-00221: 'RETURN_STRING_FUNC' is not a procedure or is undefined
ORA-06550: line 5, column 3:
Note that a similar code works fine for a stored procedure(with IN-OUT params) though; I dont see something like a PLSQLStoredFuncitionCall being present.
What am i doing wrong?

Answer 1

user8093550 wrote:
I got this working with StoredFunctionCall. To my surprise, i was not able to find PLSQLStoredFunctionCall in the version of eclipselink i am using.
Do you mean JDBC CallableStatement along with JPA? How can this be done?Don't use JPA at all as this has nothing to do with ORM persistence. Obtain the configured Datasource through JNDI, obtain connection from it, execute call, don't forget to close statement and connection.
edit:
also, the PLSQL* classes seem to be internal implementation classes that you should not be using directly as it makes it Oracle specific. Probably there is also a StoredProcedureCall that you can use to make it more portable.