Re: PostgreSQL 8.3, libpq and WHERE CURRENT OF

Ok...

Tested with 8.2.3:

Actually you can't DECLARE a cursor outside a transaction:

test1=> declare c1 cursor for select * from dbit2;
ERROR: DECLARE CURSOR may only be used in transaction blocks

That's the main reason why we don't use DECLARE CURSOR...

I understand we could use DECLARE CURSOR when a FOR UPDATE is
detected, to allow UPDATE/DELETE WHERE CURRENT OF - these only
make sense inside a transaction...

But for normal cursors, we need to support multiple active result
sets that can last outside a transaction block.

Basically, we need all what you can do with ODBC cursors.

Anyway, thanks for your help.

Seb

Tom Lane wrote:
> Sebastien FLAESCH <sf(at)4js(dot)com> writes:
>> Does a simple PQPrepare() with a SELECT statement not create a cursor on
>> the server side?
>
> No. A prepared statement is just a query plan, not a query-in-progress.
>
> The Bind/Execute messages sent by PQexecPrepared create something akin
> to a cursor, but libpq doesn't expose any API for fetching one row at a
> time in that context, so there's no way to use the "current row" anyway.
>
> regards, tom lane
>