If you don?t begin transaction your update will not work.So in Hibernate import org.hibernate.Transaction.Create object of Transaction as

Transaction tx = session.beginTransaction();

And commit the transaction as

tx.commit();

Here is an example. Updating the employee details.

public void updateEmployee(EmployeeForm employeeForm) {
                Employee employee = new Employee();

        employee.setEmpId(employeeForm.getId());
        employee.setName(employeeForm.getName());
        employee.setAddress(employeeForm.getAddress());
        employee.setSalary(employeeForm.getSalary());
        Session session = sessionFactory.openSession();
        Transaction tx = session.beginTransaction();
        session. saveOrUpdate (employee);
        tx.commit();
        session.close();
    }

What is dynamic-update ?

The dynamic-update attribute tells Hibernate whether to include unmodified properties in the SQL UPDATE statement.

Performance issue In a large table with many columns (legacy design) or contains large data volumes, update some unmodified columns are absolutely unnecessary and great impact on the system performance.