h_hibernate对象状态（H_hibernate object state）.docVIP

h_hibernate对象状态（H_hibernate object state） Java object persistence layer in Hibernate: 1. temporary status (Transient), temporary objects: the Java object in the state is called a temporary object. 1) just create a new object created by the new statement, has not been persistent in the state; 2) not in the session cache, Session without reference to it; 3) it in the database without the corresponding data. (an object in memory is not in the cache, not in database ID) 2. persistent state (Persist), persistent objects: the Java object in the persistent state is called a persistent object. 1) has been persistent in the session cache, Session has a reference to the object; 2) the persistent object corresponding to the data in the database; 3) Session in cleaning the cache, according to the attribute of persistent state object, to update the database. (an object in memory cache, database ID) 3. free state (Detached), free objects: Java object in the free state is called free objects. 1) has been persistent, but is no longer in the session cache, Session has no reference to the object; 2) free objects by the persistent object changed, so there may be corresponding to the data in the database (no other programs to delete this record, but a prerequisite) has not database data synchronization. (an object in memory cache, database ID) 4. delete state (removed), delete the object: in Java object delete state called delete object. 1) removed from a Session instance in the cache; 2) is to delete related records in the database and the corresponding object; 3) is no longer in the Session cache, and Session has plans to remove it from the database; 4) Session in cleaning the cache, SQL will execute delete statements, delete the corresponding records in the database; 5) in general, the application should not use the objects to be removed. ---------------------------------------------------------- Session = sessionFactory.openSession (session); //c1 in the state, began life cycle Cus