Great. Thanks Martin. Tim.
On Tue, Dec 14, 2010 at 03:26:41PM +0000, Martin J. Evans wrote: > On 13/12/10 21:00, Tim Bunce wrote: > > On Mon, Dec 13, 2010 at 05:30:10PM +0000, Martin J. Evans wrote: > >> See RT http://rt.cpan.org/Public/Bug/Display.html?id=63550 which started > >> this off. > >> > >> DBD::ODBC optimises calls to the do method when no parameters are > >> involved. Normally do is just a shortcut for prepare/execute except it > >> should only be for non-result-set generating statements and hence does > >> not return a statement handle. ODBC can optimise the do method to > >> simply call SQLExecDirect instead of the normal SQLPrepare/SQLExecute > >> (one round trip and other advantages). DBD::ODBC has been this way for > >> years. > >> > >> However, the person reporting this issue is attempting to use the > >> handle passed to an error handler when do fails to obtain the > >> Statement attribute. The handle DBD::ODBC passes in to the error > >> handler is the connection handle as DBD::ODBC never created a DBI > >> statement handle and hence there is no Statement attribute to access. > > > > Actually, the database handle _does_ have a Statement attribute > > http://search.cpan.org/~timb/DBI-1.615/DBI.pm#Statement > > so it does, I missed that. > > > Feel free to patch the docs to change "most recent prepare method" > > to "most recent prepare() or do() method". > > done > > >> Is DBD::ODBC breaking the rules here with this optimisation? > > > > No. > > excellent, so it is just failing to call STORE for the Statement in the > optimised do method - which I have just fixed. > > > The DBI docs for do() should have a note along the lines that > > "Drivers are free to avoid the overhead of creating an DBI statement > > handle for do(), especially if there are no parameters. In which case > > error handlers, if invoked during do(), will be passed the database handle." > > done > > > The docs for drivers using this approach should note the fact that a > > statement handle isn't created, and that error handlers like HandleErr > > will be called with the $dbh. > > done > > > Tim. > > Thanks Tim. > > BTW, I owe you an email as discussed at LPW - will try to get to it today. > > Martin > -- > Martin J. Evans > Easysoft Limited > http://www.easysoft.com >
