use DB_File;
my %database;
tie %database, 'DB_File', "bar" or die "Can't tie: $!";

##</code><code>##

tie %database, 'DB_File', "bar"

##</code><code>##

tie %database, 'DB_File', "bar", O_CREAT|O_RDWR, 0666, $DB_HASH;