Re: updateable cursors - Mailing list pgsql-patches

From Bruce Momjian
Subject Re: updateable cursors
Date
Msg-id 200307311434.h6VEY3H17813@candle.pha.pa.us
Whole thread Raw
In response to updateable cursors  (Gavin Sherry <swm@linuxworld.com.au>)
Responses Re: updateable cursors
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Gavin Sherry wrote:
> Attached is a patch implementing updatable cursors in HEAD. Regression
> test and documentation are included.
>
> Updateable cursors are used as follows:
>
> begin;
> declare foo cursor for select * from bar for update;
> fetch foo;
> update bar set abc='def' where current of foo;
> fetch foo;
> delete from bar where current of foo;
> commit;
>
>
> Two points:
>
> i) The patch doesn't implement updateable cursors for cursors marked WITH
> HOLD. I have working code for this and will send it in soon.
>
> ii) I've implemented a new snapshot type since, AFAICT, updateable cursors
> have a type of tuple visibility. Namely, if the base table of a cursor is
> updated based on that cursor, the new and old tuples are removed from the
> cursor's set of visible tuples. Like wise, deleted tuples are also
> removed.
>
> Thanks,
>
> Gavin

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