in reply to Perl DBI: Overloading statement handle

If new_dbh is in a subclass of DBI, it's pretty straightforward. There's an example of overriding the prepare method in: Subclassing the DBI.

-- Ken

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Re^2: Perl DBI: Overloading statement handle
by sherab (Scribe) on Nov 08, 2010 at 19:06 UTC
    Ken, this is a great beginning. new_dbh is not a subclass though, it's a subroutine (or maybe my knowledge of the terms is off, I admit to being fairly new with packages). new_dbh is a subroutine in MyModule::Database I can see how in the example given (thanks so much for this) where the differences are between ::db and ::st

    If I setup a prepare subroutine in MyModule::Database then that would take precedence over DBI's prepare? I would just prefer than any solution not have me tracking down every $sth in our codebase and fix it (which your example helps with greatly) or having to re-code the entire MyModule::Database module to a separation of ::db and ::st

    ......or do I need to just setup a subclass like this...
    package MyModule::Database::db;
  use vars qw(@ISA);
  @ISA = qw(DBI::db);

  sub prepare {
    my ($dbh, @args) = @_;
    my $sth = $dbh->SUPER::prepare(@args)
        or return;
    $sth->{private_mysubdbi_info} = { foo => 'bar' };
    return $sth;
  }

    [download]
    I understand my question might not even make sense. I do enjoy this the more I learn it.
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      sherab, your terminology seems fine - I think you just misread my post. I wrote: "... is in a subclass ..." not "... is a subclass ...".

      You have thrown me a bit with "I see I can't edit/delete the above. ...". I'm not sure if you're referring to the examlpe moritz provided or the one I linked to in the DBI documentation.

      Anyway, the basic idea is that you do not re-code the one million my $sth = $dbh->prepare(...) lines you currently have; nor do you re-code any existing $dbh = new_dbh(...) lines. Instead, you make a single change to your new_dbh routine which I envisage to be as simple as:

      # Old:
# return $dbh;

# New:
return bless $dbh, 'My::DBI::st';

      [download]

      Then add the code provided by moritz above that.

      Hopefully, that answers some of your questions. If you have more, feel free to ask.

      -- Ken

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[d/l]
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        Thanks Ken, the info that you and moritz provided was dead on. I was referring more to my own post in regards to deletion. I posted it before I noticed that moritz update his post. Also here's my very public thank you to you and moritz for being such saints and guiding me on this on: THANK YOU! It also gave me a new area to start practice into.
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      I see I can't edit/delete the above. The example that moritz gave at the top: WOW! It's just what I was after.
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