Re: Scrolling/Updating Cursors - Mailing list pgsql-general

From John Meyer
Subject Re: Scrolling/Updating Cursors
Date
Msg-id 528FCD8B.7060209@pueblocomputing.com
Whole thread Raw
In response to Re: Scrolling/Updating Cursors  (Kevin Wooten <kdubb@me.com>)
Responses Re: Scrolling/Updating Cursors
List 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@me.com> wrote:
>
>> My apologies for posting what is almost certainly somewhat of a repeat question but I have searched and attempted
everythingI 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/deleterows 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
provideit if possible.  I thought just using a scrollable cursor with the isolation-level set to repeatable-read would
dothe 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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