Storing Object in DBM Hash

[michael.shnitzer]

Why would the following code work in a regular hash environment but
dereference when using a DBM hash?

"Can't locate object method "docno" via package
"Document=HASH(0x4001d0cc)" (perhaps you forgot to load
"Document=HASH(0x4001d0cc)"?) at read.pl line 6."

#! /usr/bin/perl -w
use strict;

dbmopen(my %hash, "db", 0777);
$hash{mike} = new Document;
print $hash{mike}->docno;

package Document;
sub new
{
my $self = {
document_number => "DOC123",
};
bless $self;
}
sub docno
{
my $self = shift;
return $self->{document_number};
}

 

[michael.shnitzer]

On May 16, 2:25 pm, (e-mail address removed) wrote:

<snip>

Sorry for the double post.

 

[anno4000]

Why would the following code work in a regular hash environment but
dereference when using a DBM hash?

The values of DBM-Tied hashes can only be plain scalars, not references.
After all, references are live addresses in the current program, unfit
to be stored to disk.

CPAN has MLDBM (where ML stands for Multi Level) which deals with
that problem. There may be newer modules for the same purpose.

Anno