Update one column does not works - spring

Question

I want to update one column of my database. The column name is status and the type is Enum('waiting' , 'accepted' , 'rejected')
I want to update this column when I click on link:
Accept
Reject
Vacation.hbm.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.terafast.tem.model">
<class name="Vacation" table="vacations" dynamic-update="true">
<id name="id" column="REQUEST_ID">
<generator class="native" />
</id>
<property name="user" column="USER_ID" />
<property name="reason" column="REASON" />
<property name="duration" column="HOW_LONG" />
<property name="status" column="STATUS" />
<property name="start" type="date" column="START_DATE" />
<property name="created" type="date" column="CREATED_AT" />
</class>
</hibernate-mapping>
Controller
#RequestMapping(value = "/requests/action")
public String statuHandler(HttpServletRequest request, Model model) {
int id = Integer.parseInt(request.getParameter("id"));
String status = request.getParameter("a");
vacationDao.actionStatus(id, status);
return "redirect:/admin/requests";
I can successfully get these two GET values. (id , a). My VacationDAOImpl:
#Override
#Transactional
public void actionStatus(int id, String action) {
Session session = sessionFactory.openSession();
Query q = session.createQuery("from Vacation where id = :reqid ");
q.setParameter("reqid", id);
Vacation vacation = (Vacation) q.list().get(0);
vacation.setStatus(action);
session.update(vacation);
}
servlet-context.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
<!-- DispatcherServlet Context: defines this servlet's request-processing
infrastructure -->
<!-- Enables the Spring MVC #Controller programming model -->
<mvc:annotation-driven />
<!-- Handles HTTP GET requests for /resources/** by efficiently serving
up static resources in the ${webappRoot}/resources directory -->
<mvc:resources mapping="/resources/**" location="/resources/" />
<!-- Resolves views selected for rendering by #Controllers to .jsp resources
in the /WEB-INF/views directory -->
<bean
class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/views/" />
<property name="suffix" value=".jsp" />
</bean>
<context:component-scan base-package="com.terafast.tem" />
<tx:annotation-driven transaction-manager="transactionManager" />
<bean id="transactionManager"
class="org.springframework.orm.hibernate4.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactory" />
</bean>
<bean id="employeeDao" class="com.terafast.tem.dao.EmployeeDAOImpl">
<constructor-arg>
<ref bean="sessionFactory" />
</constructor-arg>
</bean>
<bean id="vacationDoa" class="com.terafast.tem.dao.VacationDAOImpl">
<constructor-arg>
<ref bean="sessionFactory" />
</constructor-arg>
</bean>
</beans>
I have seen this approach in this tutorial.
When I click on links, everything looks good. But the column value does not change. Could someone explain this problem?