Re: [Hibernate] Using CLOBs

[Ugo C. <u....@cb...>]

Gavin King wrote:
> Ahhhh the > 4000 characters bit is where you start to need
> the "for update" clause. We were wondering about that
> earlier. I think you *could* make it work like this:
> 
> s = sf.openSession();
> tx = s.beginTransaction();
> foo = new Foo();
> foo.setClob( Hibernate.createClob("") );
> s.save(foo);
> tx.commit();
> s.close();
> 
> s = sf.openSession();
> tx = s.beginTransaction();
> foo = (Foo) s.load( Foo.class, foo.getId(), LockMode.UPGRADE );
> oracle.sql.CLOB clob = (oracle.sql.CLOB) foo.getClob();
> java.io.Writer pw = clob.getCharacterOutputStream();
> pw.write(content);
> pw.close();
> tx.commit();
> s.close();
> 
> 
> Would you try that for me, please?

Tried it and it *mostly* works. The only problem seems to be that Oracle 
apparently does not distinguish between zero-length strings and NULL, so 
if you initialize the CLOB with Hibernate.createClob(""), the actual 
database column is nullified and the subsequent getClob() call returns 
null, making the clob.getCharacterOutputStream() fail with a NPE.

As a quick&dirty hack, I've changed createClob("") to createClob(" ") 
and everything seems to work ok. However, I was wondering if it is 
really necessary to open a new session. Couldn't we somehow reuse the 
former session?

	Ugo