Storable and MLDb

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

Hello Monks,
I have a problem with Storable and MLDb... substantially, because I have not confidence with these modules.

I use a mailing list software that I love, but I have a problem with data format.
This software store data not with a RDBM database, but using MLDb and Storable.

I need to create a connector (I can: this software is Open Source) in order to connect it to my personal website, but I'm not able to manipulate data with those two modules.

Ok, I go to the code,
That software use:

use Fcntl qw(
O_WRONLY 
O_TRUNC 
O_CREAT 
O_CREAT 
O_RDWR
O_RDONLY
LOCK_EX
LOCK_SH 
LOCK_NB);

use MLDBM qw(AnyDBM_File Storable);
[download]

and these are some rows, the software use to store data:

my $dbm = tie %{$self->{DB_HASH}}, 'MLDBM', $self->_db_filename, O_CRE
+AT|O_RDWR, FILE_CHMOD
[download]

then with that row, it read the file:

sysopen(DB_SCHEDULE_SAFETYLOCK, $self->_lockfile_name,  O_RDWR|O_CREAT
+, FILE_CHMOD )
[download]

I think these are all the rows involved in data storage.
If you are interesting in, the modules are these ones:

MLDb.pm
Schedules.pm

I need to read the generated files, in order to write or append there some data.

I tried in several way to read that file, but without success.
For example with:

 
use MLDBM qw(AnyDBM_File Storable);
use Storable qw(retrieve_fd);
use Fcntl qw (:DEFAULT :flock);
use FindBin qw($Bin);

tie (%hash, "MLDBM", $Bin.'mj-test-schedules', O_CREAT|O_RDWR, 0666)
    or die $!;
#    sysopen(DB_SCHEDULE_SAFETYLOCK, $Bin.'/mj-test-schedules',  O_RDW
+R|O_CREAT, 0666);
    
    
#open FILE, ">", $Bin.'/filename.txt' or die $!;

open (DF,$Bin.'/mj-test-schedules') or die $!;
flock (DF, LOCK_SH) or die $!;

$href=retrieve_fd(*DF);
close DF;


    while ( my ($key, $value) = each(%$href) ) {
        print "$key => $value\n";
    }

#print  FILE $_ while (<DB_SCHEDULE_SAFETYLOCK>) ;
    

#close FILE;

untie %hash;
[download]

In addition I don't understand (and that is probably the problem) what MLDb does and how Storable and MLDb work together.
Please, someone can help me?
Thank you very much.

Comment on Storable and MLDb Select or Download Code

Replies are listed 'Best First'.
Re: Storable and MLDb by tokpela (Chaplain) on Nov 18, 2010 at 19:25 UTC
If you are looking at saving data to disk in a hash structure, my recommendation is to use DBM::Deep. It's pure Perl, fast and very stable. `use strict; use warnings; use DBM::Deep; my $dbm = DBM::Deep->new('mj-test-schedules'); $dbm->{'some_key_name'} = 'some value'; for (keys %$dbm) ) { print "$_ => $dbm->{$_}\n"; }` [download]	[reply] [d/l]
Re^2: Storable and MLDb by saintex (Scribe) on Nov 19, 2010 at 14:07 UTC
I tried your code, but unluckily I have: DBM::Deep: Signature not found -- file is not a Deep DB at prova2.pl line 6 Br />	[reply]