Deleting data without specifying Id/key for object

sudhirph · **Joined:** Thu Apr 20, 2006 3:44 am **Posts:** 32

This is regarding deleting rows from the table w/o specifying primary key of table....

In SQL we can have a query of following type

Delete from table1 where nonprimarykeycolumn="criteria";

As far as I have seen in hibernate, session.delete() api needs an object whose key field/id is set in order to delete it.

In short can we say that hibernate doesnt provide such facilities and I have to go with a hard way of selecting a record using my criteria (in above case , nonprimarykeycolumn="criteria") , then do a session.delete() by passing individual record ........

Couldnt find an api which takes a collection of objects also which can be deleted directly......

Hope I have explained the problem properly.....any clue please

Sudhir

tenwit · **Joined:** Thu Dec 23, 2004 9:08 pm **Posts:** 2008

If you're using 3.1 or later, you can use DML to delete rows: that is, write an HQL query like this:

Code:

<query name="deleteMyClassByName">
  delete MyClass c where c.Name = :name"
</query>

There is no API for deleting a collection of objects. Either use DML like the above query, or else loop through the collection, deleting each object separately. This can be reasonably efficient if you're judicious with your use of session.flush().

sudhirph · **Joined:** Thu Apr 20, 2006 3:44 am **Posts:** 32

As far as my u/s goes , we cant have any delete/update/insert in session.getnamedquery().......

hope you got my point......

if i am going wrong, could you please tell me how do we execute given named query using hibernate session apis in java class

pepelnm · **Posted:** Mon May 08, 2006 6:13 am

What tenwit has told you is explained in hibernate reference:

Quote:

13.4. DML-style operations

You need:

Code:

session.getNamedQuery(queryName).executeUpdate();

tenwit · **Joined:** Thu Dec 23, 2004 9:08 pm **Posts:** 2008

If you're not allowed to write queries to do deletes for you, then you'll have to use the Session.delete(object) method. Those are your options. I don't know what a "u/s" is, but you'll have to change it to allow deletes, or else take the performance hit and delete objects manually.