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Re: Scrolling/Updating Cursors

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On Nov 19, 2013, at 6:33 PM, Kevin Wooten <kdubb@xxxxxx> wrote:

> My apologies for posting what is almost certainly somewhat of a repeat question but I have searched and attempted everything I can think of and cannot figure it out myself.
> 
> The basic question is… Is it possible to get a scrollable cursor that, within a transaction, can insert/update/delete rows and see those changes?
> 
> Why you ask? Because I am implementing the JDBC 4.1 spec and it (optionally) provides this ability and I’d like to provide it if possible.  I thought just using a scrollable cursor with the isolation-level set to repeatable-read would do the trick but it still seems to see no changes (inserts/updates/deletes).
> 
> Effectively I want roughly this sequence of events to work.
> 
> CREATE TABLE test (val text);
> 
> BEGIN;  # Could include ISOLATION LEVEL REPEATABLE READ
> 
> DECLARE c1 CURSOR FOR SELECT * FROM test;
> 
> FETCH ABSOLUTE 1; 	# Returns No Row
> 
> INSERT INTO test VALUES (‘1');
> INSERT INTO test VALUES (‘2');
> INSERT INTO test VALUES (‘3');
> 
> FETCH ABSOLUTE 1;  # Returns “1”
> FETCH NEXT:               # Returns “2"
> DELETE FROM test WHERE CURRENT OF c1;  # Deletes “2”
> 
> FETCH ABSOLUTE 1;  # Returns “1”
> FETCH NEXT;               # Returns “3”
> UPDATE test SET val=‘4' WHERE CURRENT OF c1;
> FETCH RELATIVE 0;    # Returns “4”
> 
> COMMIT;
> 
> Thanks!
> 
> -kw
> 


Should I take silence to mean this cannot be done?  Or should I send to -hackers?



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