Could not synchronize database state with session

问题:

Could not synchronize database state with session org.hibernate.exception.GenericJDBCException: could not update

I am getting this error while I try to update my database. There is no unique key defined in my database, but id field has been defined as Primary Key.

Here is the code of the update function :

public String updateAction(){
       Session session = null;
       try{
            SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
            session =sessionFactory.openSession();
            org.hibernate.Transaction tx = session.beginTransaction();
            Medicine medicine = (Medicine) session.load(Medicine.class, id);
            medicine.setBrandName(brandName);
            session.update(medicine);
            tx.commit();
       }
       catch(Exception ex){
            ex.printStackTrace();
       }
       finally{
            session.close();
       }
       return "index";
    }

hibernate.config.xml:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
  <session-factory>
    <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
    <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
    <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/medicine</property>
    <property name="hibernate.connection.username">root</property>
    <property name="hibernate.connection.password">root</property>
    <property name="hibernate.show_sql">true</property>
    <property name="hibernate.current_session_context_class">thread</property>
    <property name="hibernate.query.factory_class">org.hibernate.hql.classic.ClassicQueryTranslatorFactory</property>
    <property name="hibernate.jdbc.factory_class">org.hibernate.jdbc.NonBatchingBatcherFactory</property>
    <mapping resource="mediview/Medicine.hbm.xml"/>
  </session-factory>

</hibernate-configuration>

Medicine.java:

    public class Medicine  implements java.io.Serializable {

         private String id;
         private String brandName;

         public Medicine() {
         }

     public Medicine(String id) {
          this.id = id;
     }

     public Medicine(String id, String brandName) {
          this.id = id;
          this.brandName = brandName;
     }

     public String getId() {
          return this.id;
     }

     public void setId(String id) {
          this.id = id;
     }

     public String getBrandName() {
          return this.brandName;
     }

    public void setBrandName(String brandName) {
        this.brandName = brandName;
    }
}

Medicine.hbm.xml:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated 14 Aug, 2013 8:46:46 PM by Hibernate Tools 3.2.1.GA -->
<hibernate-mapping>
    <class name="mediview.Medicine" table="medicine" catalog="medicine">
        <id name="id" type="string">
            <column name="ID" length="5" />
            <generator class="assigned" />
        </id>
        <property name="brandName" type="string">
            <column name="BrandName" length="30" />
        </property>
    </class>
</hibernate-mapping>

回答1:

Do a refresh of the session state before you do the update.

Medicine medicine = (Medicine) session.load(Medicine.class, id);
session.refresh( medicine );

http://docs.jboss.org/hibernate/orm/4.0/devguide/en-US/html_single/#d0e1718