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Re: MV Keys

From: mAsterdam <mAsterdam_at_vrijdag.org>
Date: Fri, 03 Mar 2006 21:30:14 +0100
Message-ID: <4408a6c7$0$11067$e4fe514c_at_news.xs4all.nl> 






vc wrote:

> mAsterdam wrote:
> 




>>Marshall Spight wrote:

>>

>>>Jon Heggland wrote:

>>>

>>>The relational operators don't handle lists very well.


>>>

>>>myList.removeAt(3)

>>>

>>>vs.

>>>

>>>BEGIN


>>>delete from MyList where Index = 3;

>>>update MyList set Index = Index - 1 where Index > 3;

>>>COMMIT


>>

>>

>>Aside (the example surely illustrates your point)

>>could this removeAt operation possibly be useful

>>in a concurrent environment?

>>

>>You'ld never know which item you are going to scratch -

>>somebody else could have just done myList.removeAt(2).

> 
> 
> What happened to concurrency contro in your hypothetical system ?





Assuming MVCC the item which was the third item
in MyList at transaction time would be removed.
Results may be very unpleasant - that was my point -
but would this constitute a CC failure?
Received on Fri Mar 03 2006 - 21:30:14 CET












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