RE : RE : Qury on an object Locked but not in Db

[Emmanuel Dupont <em...@jwaretechnologies.com>]

Thanks a lot Charles.

That 's great !


-----Message d'origine-----
De : Charles Anthony [mailto:charles.anthony@hpdsoftware.com] 
Envoyé : jeudi 7 août 2003 16:07
À : 'OJB Users List'
Objet : RE: RE : Qury on an object Locked but not in Db

Hi,

No, not true.

"flush" will push all the INSERTS and UPDATES through to the underlying db
connection, but does *not* call connection.commit();

Any queries on the same thread will go through to the same connection, which
means you can query for the object.

So, no you can't rollback an entire ODMG transaction after a checkpoint(),
but you can roll back an entire OJB TransactioExt with a flush() 

Cheers,

Charles.

>-----Original Message-----
>From: Gelhar, Wallace Joseph [mailto:gelharwj@uwec.edu]
>Sent: 07 August 2003 15:03
>To: OJB Users List
>Subject: RE: RE : Qury on an object Locked but not in Db
>
>
>If he doesn't commit to the db, he can't query for the object, true?
>
>Then the question is can you rollback an entire ODMG 
>transaction after calling checkpoint()?
>
>-Wally
>
>-----Original Message-----
>From: Charles Anthony [mailto:charles.anthony@hpdsoftware.com] 
>Sent: Thursday, August 07, 2003 8:57 AM
>To: 'OJB Users List'
>Subject: RE: RE : Qury on an object Locked but not in Db
>
>
>Hi Emmanual,
>
>See the recent thread "Re: checkpoint problem" on the 
>developers mailing list and/or the archives.
>
>In CVS, the checkpoint methods has been changed to commit the 
>underlying database transaction, but to retain the locks. This 
>is the way other ODMG implementations handle checkpoint. 
>
>We have retained the old behaviour in a new method called 
>"flush". I believe that you should be able to cast Transaction 
>to TransactionExt and invoke "flush" e.g.
>
>Transaction tx = ......
>
>TransactionExt extendedTransaction = (TransactionExt) tx; tx.flush();
>
>Cheers,
>
>Charles
>
>
>>-----Original Message-----
>>From: Emmanuel Dupont [mailto:emmanuel.dupont@jwaretechnologies.com]
>>Sent: 07 August 2003 14:51
>>To: 'OJB Users List'
>>Subject: RE : Qury on an object Locked but not in Db
>>
>>
>>Thanks a lot for your reply Thomas,
>>
>>I'm oK to your solution; the only trouble is that I can't do a
>>Rollback avec
>>the checkpoint if I need to cancel all the operations.
>>
>>Isn't it?
>>
>>
>>-----Message d'origine-----
>>De : Mahler Thomas [mailto:thomas.mahler@itellium.com]
>>Envoyé : jeudi 7 août 2003 13:20
>>À : 'OJB Users List'
>>Objet : RE: Qury on an object Locked but not in Db
>>
>>All OQL queries are executed as SQL queries against the DB.
>>In your case the object was nos written to the DB, so a query
>>won't be able
>>to find it.
>>
>>But you could try the following:
>>Transaction tx = ...;
>>A objA = new A();
>>objA.setName("Smith");
>>tx.lock (objA);
>>tx.checkpoint();
>>
>>loadObjectByQuery();
>>
>>checkpoint writes to DB but keeps the tx open and also
>>maintains the lock on
>>objA.
>>The DB should be able to find ojbA by an SQL query then...
>>
>>cheers,
>>Thomas
>>
>>
>>> -----Original Message-----
>>> From: Emmanuel Dupont [mailto:emmanuel.dupont@jwaretechnologies.com]
>>> Sent: Wednesday, August 06, 2003 5:36 PM
>>> To: OJB Users List
>>> Subject: Qury on an object Locked but not in Db
>>> 
>>> 
>>> All,
>>> 
>>>  
>>> 
>>> Is it possible to do such thing :
>>> 
>>>  
>>> 
>>>  
>>> 
>>> A objA = new A();
>>> 
>>> objA.setName("Smith");
>>> 
>>>  
>>> 
>>> Lock (objA);
>>> 
>>>  
>>> 
>>> [...]
>>> 
>>>  
>>> 
>>> No commit is done and later if I want to work with objA,
>>> could I query to
>>> OJB to find my right A instance with getObhjectByQuery() 
>>> something else ?
>>> 
>>>  
>>> 
>>>  
>>> 
>>> 
>>
>>
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