http://www.perlmonks.org?node_id=1021876

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

Mercurial Monks,

I'm having a little trouble with accessing an old DBM file using DBI.

We have an old DBM file: 

data.pag
data.dir

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I simply want to see what's in it. Thought the DBI would be a good way, so: 
#!/usr/bin/perl -w
use strict;
use warnings;
use DBI;
use CGI;
use CGI::Carp qw(fatalsToBrowser);

# start error output
   BEGIN {
             use CGI::Carp qw(carpout);
             carpout(*STDOUT);
       }

print "Content-type:text/html\n\n";

my $db_name = 'data';
my $dbh = DBI->connect('dbi:DBM(RaiseError=1):');
my $sqlSelect = "SELECT * FROM $db_name";
my $sth = $dbh->prepare($sqlSelect) || die "Cannot prepare: " . $dbh->
+errstr();
$sth->execute() or die "Cannot execute: " . $sth->errstr();

while (my @data = $sth->fetchrow_array()) {
     print "<br>";
     for my $i (0 .. $#data) {
         print ", $data[$i]\n";
     }
}
$sth->finish;

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But what I get is 
Software error:

DBD::DBM::st execute failed: 
Execution ERROR: No write permission to sdbm file at /bla/bla/bla/DBD/
+DBM.pm line 422.
.

 at /bla/bla/bla/DBI/DBD/SqlEngine.pm line 1234.
 [for Statement "SELECT * FROM pmb_passwords_dbm"] at dumpmydbm.pl lin
+e 26.

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For the record - both the files are chmod'd 755.

Now, I was previously getting the error "no lck file" - so I simply created an empty data.lck file and that seemed to shut that up.

What's up?

Thanks.




Time flies like an arrow. Fruit flies like a banana.

Replies are listed 'Best First'.
Re: Accessing old DBM file with DBI - "write permission"?
by punch_card_don (Curate) on Mar 05, 2013 at 18:38 UTC
    On the other hand, this works: 
    #!/usr/bin/perl -w
use warnings ;
use strict ;
use DB_File ;
my %h;
unlink "data" ;
tie %h, "DB_File", "data", O_RDWR|O_CREAT, 0666, $DB_HASH or die "Cann
+ot open file 'data': $!\n";

print "Content-type:text/html\n\n";

foreach my $key (sort keys %h) {
    print "<br>$key -> $h{$key}\n";
}

    [download]
    But I get an empty result, no output. (Possible that's what's in the file, I suppose, but seems odd for a 65kb file.)



    Time flies like an arrow. Fruit flies like a banana.
[reply]
[d/l]

      Maybe you could try to create an empty DBM file and see how big it is on your system.

[reply]
        In themeantime, I found a filepath that was wrong - so now this version works perfectly. Outputs 200 lines of pairs, as sort of expected.

        So, my needs have been solved - just the mystery of the DBI version for information left.




        Time flies like an arrow. Fruit flies like a banana.
[reply]

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