Re: Transactions ISOLATIONS level

Hi Jim,
thanks for your answer. May I ask how do you define a database block, in order to
lock a certain number of rows ?
via a SQL command ?
Thanks
Francesco

"Jim Kennedy" <kennedy-family_at_home.com> ha scritto nel messaggio news:4lv_6.260536$p33.5211963_at_news1.sttls1.wa.home.com...
> For 1 an 2 I'd have to refer to the manual (which I don't have with me
 right
> now.)
> A "page" typically refers to a database block. A database block usually
 has
> more than 1 row in it. Some databases lock data by the page. Thus if you
> update a record in block 5 all the other records in block 5 are locked
 also
> (not in Oracle, but in quite a few other databases this is true.)
> Is that helpful?
> Jim
> "Francesco Marchioni" <fmarchioni_at_libero.it> wrote in message
> news:jSl_6.5944$363.259102_at_news.infostrada.it...
> > Hi all,
> > I'm studying transactions isolation levels.
> > I have some questions, hope somebody will help me:
> >
> > 1) How can I change the transaction isolation level via SQL - PL/SQL ?
> > ( I mean without administrator's tools)
> >
> > 2) When I issue a SELECT FOR UPDATE the transaction level switches
> > automatically to TRANSACTIONS_SERIALIZABLE ?
> >
> > 3) I understand row locking and table locking but what does it mean
 "page"
> > locking ??
> >
> > Thanks a lot in advance
> > Francesco
> >
> >
> >

>
> Received on Thu Jun 28 2001 - 02:13:56 CDT