Re: query before commit problem

[Guido Beutler]

Hi,

how to do it in managed enviroment?

transaction.checkpoint()

throws a not supported exception.

best regards,

Guido

Jair da Silva Ferreira J�nior wrote:

Hi,
   Thank you Thomas and Charles for your fast answers. I think I'll use
transaction.checkpoint() as Charles pointed.
   By the way, don't you think this would be a nice feature to be added to
a future OJB version? Say, when an object is persisted insinde a transaction
it would be nice if any query runned inside that transaction could "see"
that object.
Sincerely,
   Jair Jr
----- Original Message -----
From: "Charles Anthony" <[EMAIL PROTECTED]>
To: "'OJB Users List'" <[EMAIL PROTECTED]>
Sent: Friday, September 12, 2003 1:52 PM
Subject: RE: query before commit problem
 

Hi,

As Thomas says, this is by design. However, you can force the transaction
   

to
 

flush all object changes to the database, without committing the
   

underlying
 

database connection :

In RC4, you can use Transaction.checkpoint() e.g. t.checkpoint();

After RC4 (i.e. in CVS), you should be able to cast the transaction to
TransactionExt and invoke TransactionExt.flush
e.g. (TransactionExt) t).flush()

HTH,

Cheers,

Charles.

   

-----Original Message-----
From: Thomas Mahler [mailto:[EMAIL PROTECTED]
Sent: 12 September 2003 17:48
To: OJB Users List
Subject: Re: query before commit problem
Hi Jair,

ODMG transaction write to the db only on tx.commit.
Thus q is not persistent in the database when you perform the
first query!
All queries (also ODMG OQL!) are executed against the
database. So it's
obvious that loaded != q after your query.
after commiting the transaction q is stored in the DB and the second
query does find it.
Works as designed.

-Thomas

Jair da Silva Ferreira J�nior wrote:
     

Hi,
   I am using ojb1.0_rc4, ODMG api with OJB queries and
       

mysql4. The problem is that when I persist an object and run a
identity query looking for the persisted objet the query
returns null. This only happens when I persist the object and
execute the query in the same transaction. Is this behaviour
correct or is this a bug?
     

   I added some example code in the end of this email for
       

better understanding.
     

   Thanks for your help.

Sincerely,
   Jair Jr
Example code:

void doSomething(){
  Transaction t=implementation.newTransaction();
  t.begin();
  Question q=new Question();
  t.lock(q,t.WRITE);
  q.setStatement("a statement");
  q.setNumber(10);
  q.setSubject(Subject.PHYSICS);
  q.setCorrectAlternative(Alternative.A);
  Question example=new Question();
  example.setId(q.getId());
  QueryByIdentity query=new QueryByIdentity(example);
  Question loaded=(Question)
       

((HasBroker)t).getBroker().getObjectByQuery(query);
     

  //loaded==null !!! why? Shouldn't it be: loaded==q?
  t.commit();
  t=implementation.newTransaction();
  t.begin();
  query=new QueryByIdentity(example);
  loaded=(Question)
       

((HasBroker)t).getBroker().getObjectByQuery(query);
     

  //loaded!=null now! loaded==q!
  t.commit();
}
       

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