Thanks.
I'm thinking in terms of
$h->{HandleEvent} = sub { ... }
which would be called when the driver code calls something like
DBIh_EVENT(...)
Tim.
On Wed, Jul 03, 2002 at 02:37:31PM -0700, Michael Peppler wrote:
> On Wed, 2002-07-03 at 14:14, Tim Bunce wrote:
> > On Wed, Jul 03, 2002 at 11:34:17AM -0700, David L. Good wrote:
> > > Nope, DBD::ODBC doesn't have that functionality. I submitted a patch a
> > > couple of years ago to address the issue, but it kinda got lost in the
> > > shuffle and I moved on to other projects without following up on it. I
> > > hope to re-integrate the patch into the latest DBD::ODBC soon, but I'm
> > > still trying to get access to an appropriate Windows box...
> >
> > Please discuss on dbi-dev first as I'd like to consider defining a
> > standard API for that kind of functionality.
>
> OK - just to explain what this is all about:
>
> Sybase and MS-SQL have a number of commands that generate output that is
> not a normal result set. These include DBCC (database consistency
> checker), SHOWPLAN (query plan display), STATISTICS (number of
> IO/millisecs for an operation). In addition, Transact-SQL supports a
> PRINT statement that results in the same behavior, but with no "error"
> number.
>
> At the protocol level these are returned as messages, and (at least with
> Sybase) you define a callback handler in C to catch these messages and
> do something with them.
>
> For example, running a DBCC checkdb() command results in something like
> this:
>
> 2536 2 10 Checking BugTrack
> 2536 3 10 Checking sysobjects
> 2579 1 10 The total number of data pages in this table is 3.
> 7929 1 10 Table has 39 data rows.
> 2536 3 10 Checking sysindexes
> 2579 1 10 The total number of data pages in this table is 6.
> 7929 1 10 Table has 55 data rows.
> etc.
>
> In this case the third column is the "severity" of the "error" - 10
> means it's an informational message. If DBCC encounters a real error it
> will return a message with a higher severity:
>
> 11203 1 16 The command 'DBCC' is not legal when the remote object
> (xptool...TimeZone) has been defined as an RPC.
>
> I've used this functionality to write small scripts that compute the
> number of logical IOs for a SQL batch or a stored proc. This is really
> useful when you are trying to find the most efficient syntax for a query
> or a set of queries.
>
> DBD::Sybase handles this by letting the user define an error handler
> that is called before DBI realizes that there has been an error. The
> handler can then return 0 to suppress the error, or non-0 to let DBI
> handle the error (eg with RaiseError/PrintError).
>
> As an aside - at the C API level Sybase uses callbacks for lots of other
> things - for example for asynchronous requests completion notification.
>
> Michael
> --
> Michael Peppler / [EMAIL PROTECTED] / http://www.mbay.net/~mpeppler
> [EMAIL PROTECTED] / ZetaTools, Inc / http://www.zetatools.com
> ZetaTools: Call perl functions as Sybase stored procedures!
