in reply to DBI-disconnect ???

This looks like a subclassing bug. If you search google with the text of the error in quotes you will find references to this problem such as here(1), here(2), here(3) and here(4).

Link 2 above has some code, and link 3 has the trace.

The problem has hit people upgrading to DBI 1.15 from 1.13. If you post some code maybe we can find a similar problem where you might be having problems with inheritance like the code below from link 1. 

Re: DBI 1.15 subclassing bug!

----------------------------------------------------------------------
+----------

To: "dbi-users" <dbi-users@perl.org> 
Subject: Re: DBI 1.15 subclassing bug! 
From: "Phil R Lawrence" <prlawrence@Lehigh.EDU> 
Date: Mon, 9 Apr 2001 11:40:39 -0400 
Cc: "Tim Bunce" <Tim.Bunce@ig.co.uk> 
Delivered-To: mailing list dbi-users@perl.org 
Mailing-List: contact dbi-users-help@perl.org; run by ezmlm 
References: <00a501c0bede$2b70be00$5b34b480@lehigh.edu> <2001040700050
+9.F20472@ig.co.uk> 

----------------------------------------------------------------------
+----------

"Tim Bunce" <Tim.Bunce@ig.co.uk> wrote:
> On Fri, Apr 06, 2001 at 05:11:38PM -0400, Phil R Lawrence wrote:
> >   Uncaught exception from user code:
> >         DBI->disconnect is not a DBI method...
> I wouldn't want to call you a beginner, but somewhere, for some
> reason, you're executing "DBI->disconnect" or "$foo->disconnect"
> where $foo contains "DBI".

You were kind to not call me a beginner!  Nonetheless, the issue was a
screwed up @ISA ordering.  See below for the bug.

I'm glad you added the code to make DBI->disconnect blow up in DBI
1.15.  I learned a bit more about inheritance as a result.

Thanks,
Phil R Lawrence


package STORIT;
use SUBCLASS_DBI;
use vars qw( @ISA );
@ISA = qw ( SUBCLASS_DBI );

sub new {
    my $proto = shift;
    my $class = ref($proto) || $proto;
    my $s = $class->test_connect or die;

    return $s;
}

#==============================================================
package STORIT::db;
use vars qw( @ISA );
@ISA = qw( STORIT SUBCLASS_DBI::db );
    #      ^^^^^^
    #      this caused disconnect invocation to be first looked
    #      for as a DBI method (due to STORIT's @ISA) instead
    #      of as a SUBCLASS_DBI::db method (which would have
    #      correctly resolved as a DBI::db method).

#==============================================================
package STORIT::st;
use vars qw( @ISA );
@ISA = qw(SUBCLASS_DBI::st);

[download]

Replies are listed 'Best First'.
Re: Re: DBI-disconnect ???
by christopherbarsuk (Acolyte) on Aug 13, 2001 at 00:35 UTC
    Aha! This looks like a similar problem to my own... I'm a relative beginner when it comes to inheritance, so I'm sure that's where my problem lies. Here's what I'm doing: I have a class, "class_X", which is a subclass of DBI, and another class, "class_Y", which is a subclass of class_X. class_X is fairly generic, and merely extends some of the DBI functionality; class_Y is more specific to my database needs. Here's some relevant code: 
    package class_X;
require DBI;
@ISA = qw( DBI );
sub new {
     my( $class, $dns, $username, $password ) = @_;
     my %attr = ( PrintError => 1, RaiseError => 0, AutoCommit => 1 );
     my $self = DBI->connect( $dns, $username, $password, \%attr ) or 
+return;
     push @ISA, ref $self if( not grep { $_ eq ref $self } @ISA );
     return bless $self, $class;
}

sub DESTROY {
     my( $self ) = @_;
     $self->disconnect;
}
1;

package class_Y;
require class_X;
@ISA = qw( class_X );

sub new {
     my( $class ) = @_;
     my $dns = "DBI:mysql:database=XXX";
     my $user = "XXX";
     my $pwd = "XXX";
     my $self = class_X->new( $dns, $user, $pwd );
     return bless $self, $class;
}

sub DESTROY {
     my( $self ) = @_;
     $self->disconnect;
}
1;

    [download]

    This used to work fine (before upgrading DBI); now I'm having the same problem as mentioned in the links you (so graciously) forwarded.

    I haven't yet been able to wrap my brain around the problem and figure out exactly how to solve it... Any friendly nudges in the right direction?

[reply]
[d/l]
      Okay, here is my off-the-cuff guess.

      Why not change package class_Y from
      @ISA = qw( class_X );
      to
      @ISA = qw( DBI class_X );

[reply]
[d/l]
[select]
        If I do that, then none of my class_Y methods are available -- it looks in DBI, fails to find them (in DBI::db), and croaks.
[reply]

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