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Re: JDBC transaction isolation

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On 5/3/2012 10:08 PM, Richard Maher wrote:
> On May 4, 7:57 am, Arne Vajhøj<a...@vajhoej.dk>  wrote:
>> On 5/3/2012 6:23 PM, Richard Maher wrote:
>>> "Arne Vajhøj"<a...@vajhoej.dk>    wrote in message
>>> news:4fa2d5c7$0$288$14726298@news.sunsite.dk...
>>
>>>> Almost all database have it at the SQL level:
>>
>>>> http://dev.mysql.com/doc/refman/5.5/en/set-transaction.html
>>>> http://www.postgresql.org/docs/9.1/static/sql-set-transaction.htmland
>>>> http://www.postgresql.org/docs/9.1/static/transaction-iso.html
>>>> http://msdn.microsoft.com/en-us/library/ms173763.aspx
>>>> http://docs.oracle.com/cd/B10500_01/server.920/a96524/c21cnsis.htm
>>
>>> Is anyone else of the opinion that Oracle really does not support the
>>> serializable isolation level? (At least not in the way that SQL Server, Rdb,
>>> and I'm sure others do) That is, it doesn't prevent inserts to the other
>>> txn's result-set,touched-rows by locking but rather fudges some sort of
>>> snapshot/consistent-view of old data. (And even then with restrictions)
>>> Eg: - select count(*) from employees where dept_code=1;
>>
>> Oracle use MVCC instead of locking.
>>
>> And that may seem to be cheating, but I believe it meet
>> the formal isolation level definitions.
>
> Depends where you get your definition of "formal isolation
> definitions" I guess: -
>
> -----------------------------------------
>
> Definitive: -
>
> http://msdn.microsoft.com/en-us/library/ms173763.aspx

That is how SQLServer implements it.

The definitive definition is in the SQL standard.

It says that serilizable prevents:
* dirty reads
* non repeatable reads
* phantom reads

Oracle meet that as all reads will return data as they were
at the start of the transaction.

Arne

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JDBC transaction isolation markspace <-@.> - 2012-05-03 07:30 -0700
  Re: JDBC transaction isolation Arne Vajhøj <arne@vajhoej.dk> - 2012-05-03 11:53 -0400
    Re: JDBC transaction isolation markspace <-@.> - 2012-05-03 11:43 -0700
      Re: JDBC transaction isolation Arne Vajhøj <arne@vajhoej.dk> - 2012-05-03 15:00 -0400
        Re: JDBC transaction isolation Lew <lewbloch@gmail.com> - 2012-05-03 14:00 -0700
          Re: JDBC transaction isolation Arne Vajhøj <arne@vajhoej.dk> - 2012-05-03 17:13 -0400
        Re: JDBC transaction isolation "Richard Maher" <maher_rj@hotspamnotmail.com> - 2012-05-04 06:23 +0800
          Re: JDBC transaction isolation Arne Vajhøj <arne@vajhoej.dk> - 2012-05-03 19:57 -0400
            Re: JDBC transaction isolation Richard Maher <maherrj@googlemail.com> - 2012-05-03 19:08 -0700
              Re: JDBC transaction isolation Arne Vajhøj <arne@vajhoej.dk> - 2012-05-03 22:34 -0400
                Re: JDBC transaction isolation Richard Maher <maherrj@googlemail.com> - 2012-05-03 20:11 -0700
                Re: JDBC transaction isolation Richard Maher <maherrj@googlemail.com> - 2012-05-03 22:33 -0700
                Re: JDBC transaction isolation Arne Vajhøj <arne@vajhoej.dk> - 2012-05-04 08:27 -0400
                Re: JDBC transaction isolation Lew <lewbloch@gmail.com> - 2012-05-04 06:58 -0700
          Re: JDBC transaction isolation Lew <lewbloch@gmail.com> - 2012-05-03 17:15 -0700
            Re: JDBC transaction isolation Arne Vajhøj <arne@vajhoej.dk> - 2012-05-03 21:22 -0400
              Re: JDBC transaction isolation Lew <lewbloch@gmail.com> - 2012-05-03 18:32 -0700

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