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Message Posted: Mon, 19 May 2008 @ 10:29:47 GMT


     
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Subj:   Dirty read during UPDATE question
 
From:   Martin Corn

Hi,

First, I'm pretty fresh to the forum, so hello to everyone :-)

I have a question: the process running ~every two hours updates a target table, which is also access by the analysts using ODBC - through views with LOCK FOR ACCESS.

Some rows are updated, some are new; we did it in two steps as UPDATE and INSERT, to avoid rows 'disappearing' for a short period if we do it as DELETE/INSERT.

However, the execution plan for UPDATE anyways does a MERGE DELETE and MERGE; so I'm wondering if the rows deleted and inserted in one UPDATE command would be still visible to the users using 'dirty read' (lock for access), or not? If not, then we can just do DELETE / INSERT in one step...


Thanks,

Martin



     
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