如何使用 Hibernate (EntityManager) 或 JPA 调用 Oracle 函数或过程

Question

I have an Oracle function which return sys-refcursor and when I call this function using Hibernate, I am getting the following exception.

Hibernate: { ? = call my_function(?) }
 org.hibernate.exception.GenericJDBCException: could not execute query
javax.persistence.PersistenceException: org.hibernate.exception.GenericJDBCException: could not execute query
    at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1360)
    at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1288)
    at org.hibernate.ejb.QueryImpl.getSingleResult(QueryImpl.java:313)

How can I resolve this?

Oracle function

create or replace 
FUNCTION my_function(p_val IN varchar2)
    RETURN SYS_REFCURSOR
  AS
    my_cursor SYS_REFCURSOR;
  BEGIN
    OPEN my_cursor FOR SELECT emp_name FROM employees
    WHERE lower(emp_name) like lower(p_val||'%');
    RETURN my_cursor;    
  END;

My Entity class

@Entity
@javax.persistence.NamedNativeQuery(name = "getFunc", query = 
"{ ? = call my_function(:empName) }", 
 resultClass = Employee.class, hints = 
 { @javax.persistence.QueryHint(name = "org.hibernate.callable", value = "true") })
 @Table(name = "EMPLOYEES")

and in DAO

    @Override
        public void findEmployees(QueryData data,
                String empName) {

        List query = (List) entityManager.createNamedQuery("getFunc")
                         .setParameter("empName", empName)
                         .getSingleResult();
                data.setResult(query);
}

Answer 1

Oracle function or a stored procedure can be called using EntityManager in the following manner.

For Oracle Function

Create a function with sys_refcursor as return type

CREATE OR REPLACE FUNCTION my_function
(p_val IN varchar2)
    RETURN SYS_REFCURSOR
  AS
    my_cursor SYS_REFCURSOR;
  BEGIN
    OPEN my_cursor FOR SELECT emp_name FROM employees
    WHERE lower(emp_name) like lower(p_val||'%');
    RETURN my_cursor;    
  END;

In Entity class, define function as

@javax.persistence.NamedNativeQuery(name = "getFunc", query = "{? =  call
my_function(:empName) }", resultClass = Employee.class, hints = {
@javax.persistence.QueryHint(name = "org.hibernate.callable", value = "true") })

For Oracle Stored Procedure

Create procedure with sys_refcursor as first OUT parameter

CREATE OR REPLACE PROCEDURE myProcedure(p_cursor out sys_refcursor,
     p_val  in varchar2
)
 AS
BEGIN
     OPEN o_cursor FOR
          SELECT     emp_name 
             FROM     employees 
            WHERE     LOWER (emp_name) LIKE lower(p_val||'%');

In Entity class define procedure as

@javax.persistence.NamedNativeQuery(name = "getProc", query = "{ call
my_procedure(?,:empName) }", resultClass = Employee.class, hints = {
@javax.persistence.QueryHint(name = "org.hibernate.callable", value = "true") })

and finally in DAO class call function or procedure as

Query query = entityManager.createNamedQuery("getFunc"); // if procedure then getProc 
query.setParameter("empName","smith"); 
query.getResultList(); 

Thanks

Answer 2

For your function,

create or replace 
FUNCTION my_function(p_val IN varchar2)
    RETURN SYS_REFCURSOR
  AS
    my_cursor SYS_REFCURSOR;
  BEGIN
    OPEN my_cursor FOR SELECT emp_name FROM employees
    WHERE lower(emp_name) like lower(p_val||'%');
    RETURN my_cursor;    
  END;

You can define the following NamedNativeQuery :

@NamedNativeQuery(
    name = "my_function",
    query = "{ ? = call my_function( ? ) }",
    callable = true,
    resultClass = String.class
)

And, you can call the query like this:

List<String> employeeNames = entityManager
    .createNamedQuery("my_function")
    .setParameter(1, 1L)
    .getResultList();

For a stored procedure:

CREATE OR REPLACE 
PROCEDURE my_procedure(p_val IN VARCHAR2, 
    my_cursor OUT SYS_REFCURSOR,
) 
AS
BEGIN
    OPEN my_cursor FOR
    SELECT emp_name FROM employees
    WHERE lower(emp_name) like lower(p_val||'%');
END;

, you can use the following JPA 2.1 query:

StoredProcedureQuery query = entityManager
    .createStoredProcedureQuery("my_procedure")
    .registerStoredProcedureParameter(1, String.class, 
         ParameterMode.IN)
    .registerStoredProcedureParameter(2, Class.class, 
         ParameterMode.REF_CURSOR)
    .setParameter(1, 1L);
 
query.execute();
 
List<Object[]> result = query.getResultList();

Answer 3

For Procedure:

CREATE OR REPLACE PROCEDURE my_procedure(p_val IN VARCHAR2, 
  my_cursor OUT SYS_REFCURSOR) 
AS
BEGIN
  OPEN my_cursor FOR SELECT emp_name FROM employees 
      WHERE lower(emp_name) like lower(p_val||'%');
END;

Alternative Solution: Call procedure with sys_refcursor as OUT parameter without defining @NamedNativeQuery

StoredProcedureQuery query = entityManager.createStoredProcedureQuery("myProcedure");
    query.registerStoredProcedureParameter(1, void.class, ParameterMode.REF_CURSOR);
    query.registerStoredProcedureParameter(2, String.class, ParameterMode.IN);
    query.setParameter(2, "Umesh");
    List result = query.getResultList();

Answer 4

You seem to be confusing Oracle functions with Oracle stored procedures.

Functions can be invoked from a select statement - user defined functions like yours act the same way as the built-in functions, like min() and max(). They cannot be invoked by an external "call" like stored procedures can.

See http://docs.oracle.com/cd/B19306_01/server.102/b14200/functions231.htm#i1012049 for the definition of a function.

You probably will need to re-write your function as a stored procedure.

Answer 5

JPA 2.1 early draft states that there will be support for stored procedures, according to Arun Gupta from Oracle.

Support for Stored Procedures: Added support for the invocation of predefined database functions and user-defined database functions to the Java Persistence query language.

There are different variants of EntityManager.createXXXStoredProcedureQuery methods that return a StoredProcedureQuery for executing a stored procedure. Just liked @NamedQuery , there is @NamedStoredProcedureQuery that specifies and names a stored procedure, its parameters, and its result type. This annotation can be specified on an entity or mapped superclass. The name specified in the annotation is then used in EntityManager.createNamedStoredProcedureQuery . The IN, OUT, and INOUT parameters can be set and used to retrieve values passed back from the procedure. For example:

@Entity
@NamedStoredProcedureQuery(name="topGiftsStoredProcedure", procedureName="Top10Gifts")
public class Product {
 . . .
}

// In your client

StoredProcedreQuery query = EntityManager.createNamedStoredProcedureQuery("topGiftsStoredProcedure");
query.registerStoredProcedureParameter(1, String.class, ParameterMode.INOUT);
query.setParameter(1, "top10");
query.registerStoredProcedureParameter(2, Integer.class, ParameterMode.IN);
query.setParameter(2, 100);
// there are other setParameter methods for defining the temporal type of a parameter
. . .
query.execute();
String response = query.getOutputParameterValue(1);

As for when the spec is going to be finalized, or when Hibernate will support JPA 2.1, I can't say. But it might be worth keeping an eye out.

Answer 6

The previous solution doesn´t seem to work with eclipselink. I got this running with native queries under JPA with

            List result = em.createNativeQuery("select YOURFUNCTION(?) from dual ")
                      .setParameter(1, ONEPARAMETER)
                      .getResultList();