如何使用Hibernate(EntityManager)或JPA 2调用Oracle函数或过程

Question

我有一个返回sys-refcursor的Oracle函数,当我使用Hibernate 4调用这个函数时,我得到以下异常.

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)

我该如何解决这个问题？

Oracle功能

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;

我的实体课

@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")

在DAO

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

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

Answer 1

可以使用EntityManager以下列方式调用Oracle函数或存储过程.

对于Oracle功能

使用sys_refcursor创建一个函数作为返回类型

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;

在Entity类中,将函数定义为

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

对于Oracle存储过程

使用sys_refcursor第一个OUT参数创建过程

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||'%');

在Entity类中定义过程为

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

最后在DAO类调用函数或过程中作为

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

谢谢

Answer 2

对于您的功能，

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;

您可以定义以下内容NamedNativeQuery：

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

而且，您可以像这样调用查询：

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

对于存储过程：

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;

，您可以使用以下 JPA 2.1 查询：

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();