Question

I am trying to call a legacy stored function in an Oracle9i DB from Java using Hibernate. The function is declared like this:

create or replace FUNCTION Transferlocation_Fix (mnemonic_code IN VARCHAR2)
   RETURN VARCHAR2

After several failed tries and extensive googling, I found this thread on the Hibernate forums which suggested a mapping like this:

<sql-query name="TransferLocationFix" callable="true">
    <return-scalar column="retVal" type="string"/>
    select Transferlocation_Fix(:mnemonic) as retVal from dual
</sql-query>

My code to execute it is

    Query query = session.getNamedQuery("TransferLocationFix");
    query.setParameter("mnemonic", "FC3");
    String result = (String) query.uniqueResult();

and the resulting log is

DEBUG (org.hibernate.jdbc.AbstractBatcher:366) -  - about to open PreparedStatement (open PreparedStatements: 0, globally: 0)
DEBUG (org.hibernate.SQL:401) -  - select Transferlocation_Fix(?) as retVal from dual
TRACE (org.hibernate.jdbc.AbstractBatcher:484) -  - preparing statement
TRACE (org.hibernate.type.StringType:133) -  - binding 'FC3' to parameter: 2
TRACE (org.hibernate.type.StringType:133) -  - binding 'FC3' to parameter: 2

java.lang.NullPointerException
at oracle.jdbc.ttc7.TTCAdapter.newTTCType(TTCAdapter.java:300)
at oracle.jdbc.ttc7.TTCAdapter.createNonPlsqlTTCColumnArray(TTCAdapter.java:270)
at oracle.jdbc.ttc7.TTCAdapter.createNonPlsqlTTCDataSet(TTCAdapter.java:231)
at oracle.jdbc.ttc7.TTC7Protocol.doOall7(TTC7Protocol.java:1924)
at oracle.jdbc.ttc7.TTC7Protocol.parseExecuteDescribe(TTC7Protocol.java:850)
at oracle.jdbc.driver.OracleStatement.doExecuteQuery(OracleStatement.java:2599)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:2963)
at oracle.jdbc.driver.OraclePreparedStatement.executeUpdate(OraclePreparedStatement.java:658)
at oracle.jdbc.driver.OraclePreparedStatement.execute(OraclePreparedStatement.java:736)
at com.mchange.v2.c3p0.impl.NewProxyCallableStatement.execute(NewProxyCallableStatement.java:3044)
at org.hibernate.dialect.Oracle8iDialect.getResultSet(Oracle8iDialect.java:379)
at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:193)
at org.hibernate.loader.Loader.getResultSet(Loader.java:1784)
at org.hibernate.loader.Loader.doQuery(Loader.java:674)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.doList(Loader.java:2220)
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2104)
at org.hibernate.loader.Loader.list(Loader.java:2099)
at org.hibernate.loader.custom.CustomLoader.list(CustomLoader.java:289)
at org.hibernate.impl.SessionImpl.listCustomQuery(SessionImpl.java:1695)
at org.hibernate.impl.AbstractSessionImpl.list(AbstractSessionImpl.java:142)
at org.hibernate.impl.SQLQueryImpl.list(SQLQueryImpl.java:152)
at org.hibernate.impl.AbstractQueryImpl.uniqueResult(AbstractQueryImpl.java:811)
at com.my.project.SomeClass.method(SomeClass.java:202)
...

Any clues what am I doing wrong? Or any better ways to call this stored function?

---

Update: upon trying @axtavt’s suggestion, I get the following error:

ORA-14551: cannot perform a DML operation inside a query

The function indeed does extensive inserts/updates, so I guess the only way to run it would be using the stored procedure syntax. I just have no clue how to map the return value:

<sql-query name="TransferLocationFix" callable="true">
    <return-scalar column="???" type="string"/>
    { ? = call Transferlocation_Fix(:mnemonic) }
</sql-query>

What should be the column? I will try an empty value…

---

Update2: that failed as well, with an SQL Grammar Exception… So I tried the JDBC way as suggested by Pascal, and it seems to work! I added the code in an answer below.

Answer 1

I am not 100% sure and I didn’t test it but according to Hibernate’s documentation:

16.2.2. Using stored procedures for querying

Hibernate3 provides support for
queries via stored procedures and
functions. Most of the following
documentation is equivalent for both.
The stored procedure/function must return a resultset as the first
out-parameter to be able to work with
Hibernate. An example of such a
stored function in Oracle 9 and higher
is as follows:

CREATE OR REPLACE FUNCTION selectAllEmployments
    RETURN SYS_REFCURSOR
AS
    st_cursor SYS_REFCURSOR;
BEGIN
    OPEN st_cursor FOR
 SELECT EMPLOYEE, EMPLOYER,
 STARTDATE, ENDDATE,
 REGIONCODE, EID, VALUE, CURRENCY
 FROM EMPLOYMENT;
      RETURN  st_cursor;
 END;

To use this query in Hibernate you
need to map it via a named query.

<sql-query name="selectAllEmployees_SP" callable="true">
    <return alias="emp" class="Employment">
        <return-property name="employee" column="EMPLOYEE"/>
        <return-property name="employer" column="EMPLOYER"/>
        <return-property name="startDate" column="STARTDATE"/>
        <return-property name="endDate" column="ENDDATE"/>
        <return-property name="regionCode" column="REGIONCODE"/>
        <return-property name="id" column="EID"/>
        <return-property name="salary">
            <return-column name="VALUE"/>
            <return-column name="CURRENCY"/>
        </return-property>
    </return>
    { ? = call selectAllEmployments() }
</sql-query>

Stored procedures currently only
return scalars and entities.
<return-join> and
<load-collection> are not supported.

16.2.2.1. Rules/limitations for using stored procedures

You cannot use stored procedures with
Hibernate unless you follow some
procedure/function rules. If they do
not follow those rules they are not
usable with Hibernate. If you still
want to use these procedures you have
to execute them via
session.connection(). The rules are
different for each database, since
database vendors have different stored
procedure semantics/syntax.

Stored procedure queries cannot be
paged with
setFirstResult()/setMaxResults().

The recommended call form is standard
SQL92: { ? = call
functionName(<parameters>) } or { ?
= call procedureName(<parameters>}. Native call syntax is not supported.

For Oracle the following rules apply:

• A function must return a result set. The first parameter of a
  procedure must be an OUT that returns
  a result set. This is done by using a
  SYS_REFCURSOR type in Oracle 9 or
  10. In Oracle you need to define a REF CURSOR type. See Oracle literature
  for further information.

…

As I said, I’m not sure but my understanding is that you’ll have to use session.getConnection() here.