Re: computational model of transactions

Cimode wrote:
paul c wrote:
paul c wrote:
Marshall wrote:
I've been thinking about concurrency and transactions. It occurs to me
that much of the difficulty lies with the fact that multiple concurrent
transactions may operate on the same data. I begin to recall some
conversations from years past about "multiple assignment".
That is the concurrency problem, two cooks in the kitchen. I believe
the term 'transaction' was coined to give a program context for its
updates, ...
Oops, bad choice of words. Should have said "for its results". Doesn't
have to be only updates.

p
Hi paul...;)

Unfortunately, concurrency is not the only issue here...The real
underlying issue here is finding a computational model that does not
jeopardize data integrity on RM standpoint and preserves data
independence between logical and physical layer...It is a very complex
problem that can not be dealt with simplyistic SQL based solutions. I
doubt that any SQL DBMS will be able to deal with it efficiently...not
now, not in a thousand years...


I mentioned SQL only to illustrate because it seems that so many people are familiar with it (or think they are). Lock managers aren't unique to SQL products. Having said that, I think the SQL people hit on the right word with "SERIALIZABLE", assuming we would like a database to have a single value at a point in time. Rather than 'computational model', I think Marshall S is really talking about a 'serializable model', to try to put it exactly.

p
.

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