On Wed, Mar 29, 2006 at 04:49:32PM +0100, Martin J. Evans wrote: > Tim, > > Thanks, I do keep forgetting about Driver.xst. > > So, just to be clear. In DBI.pm, selectrow_array calls _do_selectrow which > calls prepare/execute/fetchsomething but this may be overriden by a driver > using selectrow_array in Driver.xst. If this is the case: > > a) is there any way for my subclassed DBI to know this?
Something like this might work: ... if exists &DBD::foo::db::selectrow_array; Also, take a look at the docs for the DBI's can() method. Though if you want to rely on that you might want to look into the implementation to check for edge cases or other subtle issues. > b) is there an easy way to identify which other methods this could apply to Nope. You'd have to use the above on all of them. Tim. > Martin > -- > Martin J. Evans > Easysoft Ltd, UK > http://www.easysoft.com > > > On 29-Mar-2006 Tim Bunce wrote: > > On Wed, Mar 29, 2006 at 11:54:32AM +0100, Martin J. Evans wrote: > >> The issue I am seeing is not quite as general as I made it sound. For > >> selectrow_hashref I see prepare/execute/fetch/fetchrow_hashref (as I > >> expect) > >> but > >> for selectrow_arrayref and selectrow_array I only see prepare. > > > > Generally... Drivers are free to implement any method in any way they > > choose. > > Their own methods don't have to call execute(), for example. > > > > Specifically... you're probably seeing the effect of the Driver.xst > > C code that most compiled drivers embed into themselves. That code > > embeds C implementations of selectall_arrayref and several other > > methods into the driver itself. The selectall_arrayref code calls the > > drivers C functions to do the work. The result is much, much, faster > > than going though perl/DBI method dispatch for each row. > > > > Tim. > > > >> Martin > >> -- > >> Martin J. Evans > >> Easysoft Ltd, UK > >> http://www.easysoft.com > >> > >> > >> On 29-Mar-2006 Martin J. Evans wrote: > >> > Hi, > >> > > >> > I have subclassed DBI and override many methods including prepare, > >> > execute > >> > and > >> > select* although they are predominantly just passed on to DBI. > >> > > >> > If I do: > >> > > >> > my $sth->prepare(sql); > >> > $sth->execute; > >> > > >> > I see the prepare and execute and pass them on to DBI. > >> > > >> > If I do: > >> > > >> > $dbh->selectrow_array(sql); > >> > > >> > I see prepare and pass it on, but do not see execute. In my case this is > >> > more > >> > than an annoyance as I cannot see any bound parameter passed to execute. > >> > > >> > e.g. > >> > > >> > $selectrow_array = [ > >> > 'select b from mytest where a = ?', > >> > undef, > >> > \1 > >> > ]; > >> > prepare: select b from mytest where a = ? > >> > !!! no execute here > >> > > >> > Or, perhaps I'm doing something wrong. > >> > > >> > Can anyone tell me if I should be seeing the execute when $dbh->select*** > >> > is > >> > called? I think I should. > >> > > >> > Thanks > >> > > >> > Martin > >> > -- > >> > Martin J. Evans > >> > Easysoft Ltd, UK > >> > http://www.easysoft.com
