the concept of the flush....

linuxaid · **Joined:** Tue Dec 30, 2003 2:35 am **Posts:** 85

when hibernate run session.flush,wait happen to the database.
does the viewpoint
<-- when hibernate run session.flush ,hibernate send sql to the database -->
is right?

michael · **Posted:** Tue Mar 16, 2004 12:02 pm

linuxaid · **Joined:** Tue Dec 30, 2003 2:35 am **Posts:** 85

when hibernate run session.flush ,hibernate send sql to the database

but i can't image
if in one transaction,what is different between run flush and not run flush?(because all sql is taken effect after hibernate commit the transaction)

if all this viewpoint i think is right,so i can't understand the meaning of run the flush in the middle of transaction?

anthony · **Posted:** Tue Mar 16, 2004 12:14 pm

it can help you debug :)

linuxaid · **Joined:** Tue Dec 30, 2003 2:35 am **Posts:** 85

but.... the total usage of the flush is only to help me to debug the code ????
really?

christian · **Posted:** Tue Mar 16, 2004 8:04 pm

Read the reference documentation, the section about "Flushing". Hibernate flushes the state of the in-memory objects to the database to ensure integrity and prevent stale data. If you modify an object and then execute a find(), you expect the find() to return the changes.

anthony · **Posted:** Wed Mar 17, 2004 3:07 am

i think what linuxaid wanted to ask is why calling "explicitly" flush() knowing it is called at commit, before find...

shl · **Posted:** Wed Mar 17, 2004 4:27 am

delpouve wrote:

it can help you debug :)

Not only for debug, in CMT environment, if you don't use tx.commit(), you have to call session.flush() manually before each session.close(). It confuses a bit.

http://forum.hibernate.org/viewtopic.php?t=928427&postdays=0&postorder=asc&start=15

michael wrote:

You can do the following:

open session
* do stuff
session.flush()
session.close()

or

open session
tx = session.beginTransaction()
* do stuff
tx.commit()
session.close()

Both will provide identical results in a CMT environment, except the second one is also easier portable to a non-CMT environment.