user75ponic user75ponic - 26 days ago 13
Java Question

How to call Oracle Function or Procedure using Hibernate 4 (EntityManager) or JPA 2

I have an Oracle function which return sys-refcursor and when I call this function using Hibernate 4 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

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

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