Re: Article about supposed "murky" future for Oracle

Serge Rielau <srielau_at_ca.eye-be-em.com> wrote in message news:<c4fe11$lld$1_at_hanover.torolab.ibm.com>...
> Thomas Kyte wrote:
>
> > So, tell me -- how do you do a report that gives -- oh say --
> > financial data (and hence must sort of return an answer that actually
> > existed in the database at some point in time) that consists of
> > multiple queries -- each of which must be read consistent not only
> > individually -- but with respect to eachother.
> Wouldn't you have some sort of a cut off time? I mean you would look at
> all transactions that happened for a given time-period using a timestamp.

you mean you'd have to effective date/end date each record

and train all developers and end uses how to properly query this data (thats 'hard')

and make sure they do it consistently and correctly

and write the code to maintain these fields

and put up with the overhead of searching for the right records using sql each time

sure -- you could do that. Or, you could just set your isolation read only or serializable (or using flashback, set your point in time to say "midnight" -- even if the report started at 12:15am) and run your queries.

> If the DBMS kept running sums in the operational system then it buys
> itself a "writers blocking writers" problem in the normal operations and
> it wouldn't be normalized either.

not saying they would keep running totals -- I'm saying "i need a report with accurate information"

> As a result the data that is being looked at is stable. RR/Serializable
> (if chosen) ensures no-one is trying to undo a previously committed
> transaction but it does not harm incoming new transactions.

RR/Serializable blocks most incoming new transactions -- if that is not "harmful"....

>
> Cheers
> Serge
Received on Thu Apr 01 2004 - 08:23:42 CST