Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

I have troube using Class::DBI and Class::MethodMaker together.
the following code produdes the error as shown below. any ideas?
package Foo::DBI;
        use base 'Class::DBI';
        use Class::MethodMaker
                new_with_init   => 'new';

        sub init
        {
          my $self->set_db('Main', 'dbi:mysql:database', 'user', 'pass
+word');
        }

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Error-Output: 
[Wed Sep 24 12:39:38 2003] [error] [client 10.0.1.48] Premature end of
+ script headers: test.cgi
[Wed Sep 24 12:39:38 2003] [error] [client 10.0.1.48] Can't connect(),
+ no database driver specified and DBI_DSN env var not set at blib/lib
+/Class/MethodMaker.pm (autosplit into blib/lib/auto/Class/MethodMaker
+/new_with_init.al) line 259

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Replies are listed 'Best First'.
Re: problem using Class::DBI with Class::Methodmaker
by perrin (Chancellor) on Sep 24, 2003 at 12:57 UTC
    What are you trying to do? Class::DBI already provides a constructor (several in fact) for your class, and you have to to use it if you want Class::DBI to work.
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Re: problem using Class::DBI with Class::Methodmaker
by Anonymous Monk on Sep 24, 2003 at 10:49 UTC
    ok, i got some ideas and thoughts about this on #perl, actually even after changing the code to 
    package Foo::DBI;
        @Foo::DBI::ISA = qw( Class::DBI );
        use Class::MethodMaker
                new_with_init   => 'new';

        sub init
        {
          my $self=shift;
          $self->set_db('Main', 'dbi:mysql:my_database', 'user', 'xxxx
+');
        }

    [download]
    fxn (#perl) pointed me to the following problems: 
    fxn	you would need to debug whether the underlying implementation is compatible
fxn	this is a problem inherent of the openess of OOP in Perl
fxn	Class::MethodMaker uses a hashref IIRC
fxn	whereas I would expect Class::DBI to be a tied hash behind the scenes (just a guess)
    any ideas or suggestions for that? thanks
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Re: problem using Class::DBI with Class::Methodmaker
by simonm (Vicar) on Sep 24, 2003 at 17:08 UTC
    I don't think Class::MethodMaker is really the problem.

    That use Class::MethodMaker new_with_init   => 'new'; line is equivalent to adding the following subroutine declaration to your package: 

        sub new {
      my $class = shift;
      $class = ref $class || $class;
      my $self = {};
      bless $self, $class;
      $self->init(@_);
      $self;
    };

    [download]

    Perhaps the problem is that Class::DBI provides its own constructor method which it expects you to call?

    You might be able to do something more like the following: 

            package Foo::DBI;
        use base 'Class::DBI';

        sub new {
          my $self = (shift)->SUPER::new( @_ );
          $self->init();
          return $self;
        }

        sub init {
          my $self->set_db('Main', 'dbi:mysql:database', 'user', 'pass
+word');
        }

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[d/l]
[select]
Re: problem using Class::DBI with Class::Methodmaker
by zengargoyle (Deacon) on Sep 25, 2003 at 01:34 UTC

    it's something to do with namespaces. try this which works.

    package Foo::DBI;
use base 'Class::DBI';

use Class::MethodMaker
  new_with_init   => 'new';

sub init
{
  my $self = shift;
  __PACKAGE__->set_db('Main', 'dbi:Pg:dbname=kickcache;host=somewhere.
+sub.dom');
  __PACKAGE__->table('kickcache');
  __PACKAGE__->columns( All => qw( session username ) );
} 

sub test {
        my $x = Foo::DBI->new;
        my $y = $x->retrieve(0);
        print $y->username, $/;
}

1;

__END__
$ perl -MFoo::DBI -e 'Foo::DBI->test()'
1064452728

# which happens to be the right answer...

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[d/l]
Re: problem using Class::DBI with Class::Methodmaker
by parasew (Beadle) on Sep 24, 2003 at 22:48 UTC
    maybe you want to take a look also at Class::Accessor, which is a Module used already in Class::DBI. therefore they both should work much more nice together...
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      but Class::Accessor doesn't seem to have a that huge functionalty, such as Class::MethodMaker has... any comments on that?
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