Perhaps you are looking for a NDBM_File or DB_File database. basically is allows one to create a file to store a simple hashed array. I would suggest reading up on the tie function and the documentation for the AnyDBM_File module.

use NBDM_File;
tie %hash, '/some/path/databasefile',  1, 0;
$hash{'key'} = 'value';
my $value = $hash{'key'};
untie %hash;
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Although tie is pretty good for simple hashes, it does not store complex objects. In order to do that you can simply use a FreezeThaw to change between a complex memory structure and a string. So something like this...

use FreezeThaw qw/freeze thaw/;

# Store information
my $cdobject = { 'title' => 'My Music', 'author' => 'Me',  
      'tracks' => [ {'title' => 'songA', 'length' => '1:00'},
            {'title' => 'songB', 'length' => '1:50'} ] };
my $cdfrozen = freeze($cdobject);
$hash{ $cdobject->{'title'} } = $cdfrozen.

# Retrieve information
my $cd = thaw( $hash{'My Music'} );
printf "Album %s with %s tracks\n", $cd->{'title'}, 
     $#{$cd->{'tracks'}};
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Then, of course, you can get fancy. Like setting up a different hash for each index you want. And in order to keep the data 'synchronized' you can have the index hashes point to an entry ID with a master hash storing each entry ID mapped to a frozen object. Or better yet, even roll your own Perl module that will do all the management of the index databases and the main database for you and just have a simple object oriented interface to work with the information. However at that point you have basically written your own RDBMS and might as well setup MySQL or PostgreSQL.