Efficient Delete in Hibernate

Question

I know that the following code will delete the record with id = 5 from database:

 Query query = session.createQuery("delete from Class where id = 5");
 query.executeUpdate();

But before i delete it, need to save this record's data in a variable. So I want to select id = 5, and after some code, I delete it. It's not efficient if i use two distinct query for them. Because in this way we search database for this item two times.

query = session.createQuery("from Class where id = 5");
//somecode
query = session.createQuery("delete Class where id = 5");
...

So i need a more efficient way to do this, and do it better.

It would be nice to explain why you think this is not a good way of coding it. Otherwise it just seems like another "give me code that works" question. — Jon Taylor
– Jon Taylor, Commented Jul 4, 2012 at 10:42
yes, it's right. i did'n want to code like them, because, it must search in database 2 times. but in the answers right method for this task is explained. — Mohammad ali baghershemirani
– Mohammad ali baghershemirani, Commented Jul 4, 2012 at 11:09
I know, however my point still stands, you state that its a bad idea to do it that way but never explained why you thought that. — Jon Taylor
– Jon Taylor, Commented Jul 4, 2012 at 11:33
@JonTaylor he said: Because in this way we search database for this item two times. — Mohammad Jafar Mashhadi
– Mohammad Jafar Mashhadi, Commented Dec 26, 2013 at 14:45

KV Prajapati · Accepted Answer · 2012-07-04 10:42:36Z

4

No need to create query to delete a record.

query = session.createQuery("from Class where id = 5");
List list=query.list();
if(list.size()!=0)
 {
   ClassName obj = (ClassName)list.get(0);
   session.delete(obj);
  }

answered Jul 4, 2012 at 10:42

KV Prajapati

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1 Comment

Alex Barnes Over a year ago

In addition, if this 'id' field is the @Id you can use session.get() to obtain your object in place of session.createQuery.

JB Nizet · Accepted Answer · 2012-07-04 10:44:03Z

3

Hibernate has a Session.delete() method. Use it if you already have a reference to the entity to remove. No need for a query.

This would also apply the potential cascades configured on associations, which a delete query does not.

answered Jul 4, 2012 at 10:44

JB Nizet

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