From: | John Meyer <johnmeyer(at)pueblocomputing(dot)com> |
---|---|
To: | pgsql-general(at)postgresql(dot)org |
Subject: | Re: Scrolling/Updating Cursors |
Date: | 2013-11-22 21:32:59 |
Message-ID: | 528FCD8B.7060209@pueblocomputing.com |
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Thread: | |
Lists: | pgsql-general |
Why not both? I keep on searching even when I post up a question.
On 11/22/2013 2:27 PM, Kevin Wooten wrote:
> On Nov 19, 2013, at 6:33 PM, Kevin Wooten <kdubb(at)me(dot)com> 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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