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Re: Transactions ISOLATIONS level

From: Jim Kennedy <kennedy-family_at_home.com>
Date: Thu, 28 Jun 2001 01:00:48 GMT
Message-ID: <4lv_6.260536$p33.5211963@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 Wed Jun 27 2001 - 20:00:48 CDT

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