FreeTDS Development Group

["Lowden, James K" <LowdenJK AT bernstein.com>]

> From: Bernt Andreas Drange [mailto:Bernt.Andreas.Drange AT imr.no]
> Sent: September 11, 2003 2:45 AM
> 
> Oh, and to clarify a bit: My question did not relate to queries that
> return two result sets at once, but to whether it is possible 
> to run one
> query first, and then another - allowing you to work with two $results
> at once.. 

Bernt, 

The upper layers can play games, but as far as the server is concerned, a
client must receive all rows from a result set, or cancel the query, before
issuing a new query on the same connection.  That's a property of the TDS
protocol.  

If you issue a query that returns 100 rows, fetch 20 rows, and then attempt
to issue a new query, you should get an error message indicating there are
"pending results".  The server requires you to either fetch the remaining 80
rows, or cancel the query (allowing it to discard the rows) before
proceeding.  

Server-side cursors on Sybase change things a bit.  FreeTDS doesn't support
them (yet), however.  

When I said "play games", I meant that nothing prevents a higher layer from
opening a new connection to manage a second result set.  Perl's DBD::Sybase
does that sometimes.  From what I read about PHP, I doubt it does anything
so fancy.  

HTH.  

--jkl
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