Making Entity Immutable

Making Entity Immutable

You can use mutable attribute of class element in class mapping metadata. Default value of this attribute is true. If you make class as a immutable i.e mutable="false" than no UPDATE SQL statement will not be execute for this class or Entity.

If i run the following code than it will not execute any UPDATE SQL statement, 

Note: we have set mutable="false" for this case,

public class HibernateTest {

private final static Logger LOGGER = Logger.getLogger(HibernateTest.class); 

/**

* @param args

*/

public static void main(String[] args) {

LOGGER.info("starting of main method");

Session session = HibernateUtil.getSessionFactory().openSession();

Transaction txn = session.beginTransaction();

Item item = (Item) session.get(Item.class, 1L);

item.setItemName("Nokia");

session.saveOrUpdate(item);

txn.commit();

session.close();

HibernateUtil.shutDown();

}

}

 

See the generated comments on console:

Oct 10, 2012 4:11:12 PM org.hibernate.tool.hbm2ddl.SchemaUpdate execute

INFO: updating schema

Oct 10, 2012 4:11:12 PM org.hibernate.cfg.Configuration secondPassCompile

INFO: processing extends queue

Oct 10, 2012 4:11:12 PM org.hibernate.cfg.Configuration secondPassCompile

INFO: processing collection mappings

Oct 10, 2012 4:11:12 PM org.hibernate.cfg.Configuration secondPassCompile

INFO: processing association property references

Oct 10, 2012 4:11:12 PM org.hibernate.cfg.Configuration secondPassCompile

INFO: processing foreign key constraints

Oct 10, 2012 4:11:12 PM org.hibernate.tool.hbm2ddl.TableMetadata <init>

INFO: table found: HibernateTest.item

Oct 10, 2012 4:11:12 PM org.hibernate.tool.hbm2ddl.TableMetadata <init>

INFO: columns: [created_date, modified_date, item_name, item_id, item_amount]

Oct 10, 2012 4:11:12 PM org.hibernate.tool.hbm2ddl.TableMetadata <init>

INFO: foreign keys: []

Oct 10, 2012 4:11:12 PM org.hibernate.tool.hbm2ddl.TableMetadata <init>

INFO: indexes: [primary]

Oct 10, 2012 4:11:12 PM org.hibernate.tool.hbm2ddl.SchemaUpdate execute

INFO: schema update complete

Oct 10, 2012 4:11:12 PM org.hibernate.impl.SessionFactoryImpl checkNamedQueries

INFO: Checking 0 named queries

Hibernate: /*load com.Item*/select item0_.ITEM_ID as ITEM1_0_, item0_.ITEM_NAME as ITEM2_0_0_, item0_.ITEM_AMOUNT as ITEM3_0_0_, item0_.CREATED_DATE as CREATED4_0_0_, item0_.MODIFIED_DATE as MODIFIED5_0_0_ from ITEM item0_ where item0_.ITEM_ID=?

Oct 10, 2012 4:11:12 PM org.hibernate.impl.SessionFactoryImpl close

INFO: closing