Hibernate Session operation

1. Increase

@Test      Public void Add () {        configuration cfg=new  configuration (). Configure ();        Sessionfactory Factory=cfg.buildsessionfactory ();        Session session=factory.opensession ();        Emps emp=new Emps ("Cat", "female", 15,30,2000);        Session.save (EMP);        Session.close ();        Factory.close ();    }

2. Enquiry

@Test      Public void Query1 () {        configuration cfg=new  configuration (). Configure ();        Sessionfactory Factory=cfg.buildsessionfactory ();        Session session=factory.opensession ();        Emps emp= (Emps) session.get (Emps.  Class, 1005);        System.out.println (Emp.tostring ());        Session.close ();        Factory.close ();    }

Lazy Loading:

Get method: Call to issue SQL query immediately

Load method: Call does not emit SQL when we need to use this object to query

Query:

You can use the Uniqueresult () method when there is only one query result.

Emps emp= (Emps) Query.uniqueresult ();

Paging:

        Query query = Session.createquery ("from Emps");         // page        out // take results        from the beginning of the first few Query.setfirstresult (0);         // up to a few results        per page Query.setmaxresults (3);        List<Emps> list = Query.list ();    

3. Modify the table-Create transaction required

@Test      Public void Update () {        configuration cfg=new  configuration (). Configure ();        Sessionfactory Factory=cfg.buildsessionfactory ();        Session session=factory.opensession ();        Transaction ts=session.begintransaction ();        Emps emp= (Emps) session.get (Emps.  Class, 1005);        Emp.setage (+);        Session.update (EMP);        Ts.commit ();        System.out.println (Emp.tostring ());        Session.close ();        Factory.close ();    }

4. Delete

@Test      Public void Delete () {        configuration cfg=new  Configuration (). Configure ();        Sessionfactory Factory=cfg.buildsessionfactory ();        Session session=factory.opensession ();        Transaction ts=session.begintransaction ();         // deleted by ID;        Emps emp=New  Emps ();        Emp.setid (1019);        Session.delete (EMP);        Ts.commit ();        Session.close ();        Factory.close ();    }

5. Querying all Objects (HQL)

Hql:hibernate Query Language

@Test      Public void Query2 () {        configuration cfg=new  configuration (). Configure ();        Sessionfactory Factory=cfg.buildsessionfactory ();        Session session=factory.opensession ();         = Session.createquery ("from Emps"); // Emps is a class name        list<emps> list = query.list ();          for (Emps e:list) {            System.out.println (e);        }        Session.close ();        Factory.close ();    }

6. Criteria Query

@Test Public voidQuery3 () {Configuration cfg=NewConfiguration (). Configure (); Sessionfactory Factory=cfg.buildsessionfactory (); Session Session=factory.opensession (); //Criteria Query: Hibernate object-oriented query (no statement)Criteria Criteria=session.createcriteria (Emps.class); List<Emps> list =criteria.list ();  for(Emps e:list) {System.out.println (e);        } session.close ();    Factory.close (); }

7.SQL Query

@Test Public voidQuery4 () {Configuration cfg=NewConfiguration (). Configure (); Sessionfactory Factory=cfg.buildsessionfactory (); Session Session=factory.opensession (); SQLQuery Createsqlquery= Session.createsqlquery ("SELECT * from Emps"); Createsqlquery.addentity (Emps.class); List<Emps> list =createsqlquery.list ();  for(Emps e:list) {System.out.println (e);        } session.close ();    Factory.close (); }

Hibernate Session operation