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in reply to Re: can't manage to use BerkeleyDB::Env
in thread can't manage to use BerkeleyDB::Env

Ok. Well, to tell the whole story I only used DB_File in this simple example.

The thing is that I already have a db which I know has an environnement in it (I've already opened it with an other perl program). What I wanted to do was to retrieve some data from its Env, so I wanted to explore a bit the structure of an BerkeleyDB::Env class.

So I tried to create a "detached" env:

use BerkeleyDB;
my $env = new BerkeleyDB::Env -Home => "/tmp"
    or die "could not create env";

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And then I do raise the "could not create" exception.

Shouldn't it be possible to create a brand new environnement, detached from any database?

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Re^3: can't manage to use BerkeleyDB::Env
by Anonymous Monk on Aug 23, 2012 at 10:45 UTC
    Well, according to the docs, it is, provided you follow the docs (use flags) 
    #!/usr/bin/perl --
use strict; use warnings; use Data::Dump;
use BerkeleyDB;

for my $opts ( [], [-Flags  => DB_CREATE| DB_INIT_CDB | DB_INIT_MPOOL]
+ ){
    my $env = BerkeleyDB::Env->new(
        -Home => './home',
        @$opts,
    ) or warn "cannot open environment: $BerkeleyDB::Error\n";
    dd $env, [ glob './home/*' ];
}
__END__

    [download]

    On first run it doesn't exist, so first try, without flags, fails -- you need flags to initialize 

    $ perl berkeleydb.env.pl
cannot open environment: No such file or directory
(undef, [])
(
  bless([12346044], "BerkeleyDB::Env"),
  [
    "./home/__db.001",
    "./home/__db.002",
    "./home/__db.003",
    "./home/__db.004",
  ],
)

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    On second run both tries work, because its already initialized 

    $ perl berkeleydb.env.pl
(
  bless([10087228], "BerkeleyDB::Env"),
  [
    "./home/__db.001",
    "./home/__db.002",
    "./home/__db.003",
    "./home/__db.004",
  ],
)
(
  bless([12336228], "BerkeleyDB::Env"),
  [
    "./home/__db.001",
    "./home/__db.002",
    "./home/__db.003",
    "./home/__db.004",
  ],
)

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[d/l]
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      Ok, thanks.

      I was mis-leaded by the following statement in the BerkeleyDB man page:

      « All the parameters to the BerkeleyDB::Env constructor are optional. »

      Well, not so true then.

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        Well, not so true then.

        :) Well sure its true :) its just that success isn't guaranteed -- its like open, even filename is optional, but it doesn't mean you'll open a file

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