DB_File tie failed

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

I got this simple script that i can't get it work. I am trying to tie an existing db but it dies when tie.
the db file exists in the same dir where the perl script is. and it's read/writable by me.

#!/usr/bin/perl -w

use strict;
use DB_File;

my %db;
tie (%db,'DB_File',"mydb.db",O_RDONLY) or die "tie : $!";
untie %db;
[download]

it simply dies with tie : at t.pl line 9.

I followed tye's suggestion and traced it with perl debugger. but I don't see anything wrong (still new to perl debugger) here is the trace if it helps

main::(t.pl:9): tie (%db,'DB_File',"movies.db",O_RDONLY) or die "tie :
+ $!";
  DB<1> s
Fcntl::AUTOLOAD(/usr/lib/perl5/5.6.0/i386-linux/Fcntl.pm:203):
203:        (my $constname = $AUTOLOAD) =~ s/.*:://;
  DB<1> s
Fcntl::AUTOLOAD(/usr/lib/perl5/5.6.0/i386-linux/Fcntl.pm:204):
204:        my $val = constant($constname, 0);
  DB<1> s
Fcntl::AUTOLOAD(/usr/lib/perl5/5.6.0/i386-linux/Fcntl.pm:205):
205:        if ($! != 0) {
  DB<1> s
Fcntl::AUTOLOAD(/usr/lib/perl5/5.6.0/i386-linux/Fcntl.pm:216):
216:        *$AUTOLOAD = sub { $val };
  DB<1> s
Fcntl::AUTOLOAD(/usr/lib/perl5/5.6.0/i386-linux/Fcntl.pm:217):
217:        goto &$AUTOLOAD;
  DB<1> s
Fcntl::__ANON__[/usr/lib/perl5/5.6.0/i386-linux/Fcntl.pm:216](/usr/lib
+/perl5/5.6.0/i386-linux/Fcntl.pm:216):
216:        *$AUTOLOAD = sub { $val };
  DB<1> s
DB_File::TIEHASH(/usr/lib/perl5/5.6.0/i386-linux/DB_File.pm:264):
264:        tie_hash_or_array(@_) ;
  DB<1> s
DB_File::tie_hash_or_array(/usr/lib/perl5/5.6.0/i386-linux/DB_File.pm:
+244):
244:        my (@arg) = @_ ;
  DB<1> s
DB_File::tie_hash_or_array(/usr/lib/perl5/5.6.0/i386-linux/DB_File.pm:
+246):
246:        my $tieHASH = ( (caller(1))[3] =~ /TIEHASH/ ) ;
  DB<1> s
DB_File::tie_hash_or_array(/usr/lib/perl5/5.6.0/i386-linux/DB_File.pm:
+249):
249:            if @arg >= 5 && ref $arg[4] && $arg[4] =~ /=HASH/ && t
+ied %{ $arg[4] } ;
  DB<1> s
DB_File::tie_hash_or_array(/usr/lib/perl5/5.6.0/i386-linux/DB_File.pm:
+252):
252:        if ($db_version > 1 and defined $arg[4] and $arg[4] =~ /RE
+CNO/ and
253:            $arg[1] and ! -e $arg[1]) {
  DB<1> s
DB_File::tie_hash_or_array(/usr/lib/perl5/5.6.0/i386-linux/DB_File.pm:
+259):
259:        DoTie_($tieHASH, @arg) ;
  DB<1> s
tie :  at t.pl line 9, <IN> line 14.
Debugged program terminated.  Use q to quit or R to restart,
[download]

line 244: my (@arg) = @_ ; here @_ contains DB_File,mydb.db,0

Comment on DB_File tie failed Select or Download Code

Replies are listed 'Best First'.
Re: DB_File tie failed by jZed (Prior) on Jun 03, 2004 at 16:53 UTC
Try: `eval { tie %h, $tie_class, @tie_args }; die "Cannot tie($tie_class @tie_args): $@" if $@;` [download]	[reply] [d/l]
Re: DB_File tie failed by eserte (Deacon) on Jun 03, 2004 at 19:05 UTC
Maybe the database is corrupted? Sometimes it helps to dump and reload the database file with db_dump and db_load. It might be a problem of the berkeley db library itself --- recently I was surprised that I cannot tie RECNO databases in O_RDONLY mode (berkeley db 4.0 on RedHat 8.0). In that case there was also no error message in $!.	[reply]
Re^2: DB_File tie failed by Qiang (Friar) on Jun 07, 2004 at 05:20 UTC
I have updated the DB_File and Perl to the latest. but still no luck. I have no problem working on another db file which generated a while ago using the same script. finally, i came to realize that the db I am having problem were generated on a windows machine using activeperl. once I regenerate the db file under the system i am working on(linux) , it is okay now. thanks again for your help.	[reply]
Re: DB_File tie failed by borisz (Canon) on Jun 03, 2004 at 16:56 UTC
Hi, Perhaps your file did ot exists? perl 5.6.0 is pretty old too. Try it with `tie (%db,'DB_File',"mydb.db") or die "tie : $!";` It creates the file if it is not there. Sure I admit there should be a better errormessage, but I get a good one with perl 5.8.3. Boris	[reply] [d/l]