Re: shre lock vs. exclusive lock

From: VC <boston103_at_hotmail.com>
Date: Sat, 03 Apr 2004 15:46:00 GMT
Message-ID: <Y_Abc.168604$_w.1802066@attbi_s53>

Hello,

"Ryan Gaffuri" <rgaffuri_at_cox.net> wrote in message news:1efdad5b.0404030603.32dcd24_at_posting.google.com...
> I am reading a standard university database textbook and I am
> attempting to apply it to Oracle. Here is the book... it's used all
> over the place
>
>
>

http://www.amazon.com/exec/obidos/tg/detail/-/0072554819/qid=1081000904/sr=1 -1/ref=sr_1_1/103-1148263-1387019?v=glance&s=books
>
>
> In the chapter on Locking it states that a share lock is used to lock
> on reads, so that other sessions can read, but cannot right. An
> exclusive lock is used on writes and no other session can access the
> data.
>
> Now oracle doesn't lock on reads and when it does writes, other uses
> can still read. So how does Oracle define share locks vs. exclusive
> locks in contrast to my book?
>

A simple answer is that Oracle does not have row level share read locks but does have table level share read locks.

http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96524/c21cnsis .htm#3188

VC Received on Sat Apr 03 2004 - 09:46:00 CST