There may be times where you want to retrieve data from DB, do some changes in it and save back the data.In such a time the connection could not be kept open for the whole period of time since db connections are resource intensive. <\/p>\n
So I will fetch the object -> close the Session -> Do some operations -> Open new session again -> Update the Object -> Close the Session.<\/p>\n
\r\n\tsessionFactory = createSessionFactory();\r\n\tSession objSession = sessionFactory.openSession();\r\n\tobjSession.beginTransaction();\t\t\r\n\tUsers objUser = objSession.get(com.mugil.user.Users.class, 11);\r\n\tobjSession.getTransaction().commit();\r\n\tobjSession.close();\r\n\r\n\tobjUser.setUserName("Updated");\r\n\r\n\tobjSession = sessionFactory.openSession();\r\n\tobjSession.beginTransaction();\r\n\tobjSession.update(objUser);\r\n\tobjSession.getTransaction().commit();\r\n\tobjSession.close();\r\n<\/pre>\nNow the way Hibernate works is it first runs the select query for the value which should be changed and updates the value.So 2 queries for the whole process.Now there are chance’s the value fetched from DB may or may not be changed.So we can do a check which checks the fetched and updated value for uniquess before running the update query.If the fetched data is not changed th update query wont be run.<\/p>\n
The Annotation for that is as below.<\/p>\n
\r\n @Entity\r\n @org.hibernate.annotations.Entity(selectBeforeUpdate=true)\r\n<\/pre>\n","protected":false},"excerpt":{"rendered":"There may be times where you want to retrieve data from DB, do some changes in it and save back the data.In such a time the connection could not be kept open for the whole period of time since db connections are resource intensive. So I will fetch the object -> close the Session ->… Continue reading