dbm problem HELP!

[Tom]

I can write to, close aand reopen a dbm file with hashes of hasjed of hashes
and everything is OK.
Data I write is read back just fine.
However, when I run the program again later on and use the same exact code
to reopen the dbm, al the data is gone.

Here is a snippet of what I am doing:

dbmopen (%nd,$ndbfile,0666) || die "Can't dbmopen $ndbfile: $!";

$stk = "ABC";
$datecode = "20030914";
$druntime = "700";
$data = "12345";

$nd{$stk}{$datecode}{$druntime}{Data} = $data;

dbmclose (%nd) || die "Can't dbmclose $ndbfile: $!";

dbmopen (%nd,$ndbfile,0666) || die "Can't dbmopen $ndbfile: $!";
print "Data: $nd{$stk}{$datecode}{$druntime}{Data}\n";
dbmclose (%nd) || die "Can't dbmclose $ndbfile: $!";

-------
Data: 12345
-------

However, if I rerun the script with just the following, I get this:

$stk = "ABC";
$datecode = "20030914";
$druntime = "700";
$data = "12345";

dbmopen (%nd,$ndbfile,0666) || die "Can't dbmopen $ndbfile: $!";
print "Data: $nd{$stk}{$datecode}{$druntime}{Data}\n";
dbmclose (%nd) || die "Can't dbmclose $ndbfile: $!";

Use of unitialized value in concatenation (.) at C: blah, blah, blah
Date:

Apparently, there is a problem accessing the dbm file, though it is there.
Any help would be greatly appreciated, thanks,
Tom

[Tom]

when I just try to assign a sub hash to the top, it never gets assigned
regardless of which run, by the way.

"Tom" <tom@nosleep.net> wrote in message news:3f6548dc$1@nntp0.pdx.net...

> I can write to, close aand reopen a dbm file with hashes of hasjed of

hashes

> and everything is OK.
> Data I write is read back just fine.
> However, when I run the program again later on and use the same exact code
> to reopen the dbm, al the data is gone.
>
> Here is a snippet of what I am doing:
>
> dbmopen (%nd,$ndbfile,0666) || die "Can't dbmopen $ndbfile: $!";
>
> $stk = "ABC";
> $datecode = "20030914";
> $druntime = "700";
> $data = "12345";
>
> $nd{$stk}{$datecode}{$druntime}{Data} = $data;
>
> dbmclose (%nd) || die "Can't dbmclose $ndbfile: $!";
>
> dbmopen (%nd,$ndbfile,0666) || die "Can't dbmopen $ndbfile: $!";
> print "Data: $nd{$stk}{$datecode}{$druntime}{Data}\n";
> dbmclose (%nd) || die "Can't dbmclose $ndbfile: $!";
>
> -------
> Data: 12345
> -------
>
> However, if I rerun the script with just the following, I get this:
>
> $stk = "ABC";
> $datecode = "20030914";
> $druntime = "700";
> $data = "12345";
>
> dbmopen (%nd,$ndbfile,0666) || die "Can't dbmopen $ndbfile: $!";
> print "Data: $nd{$stk}{$datecode}{$druntime}{Data}\n";
> dbmclose (%nd) || die "Can't dbmclose $ndbfile: $!";
>
> Use of unitialized value in concatenation (.) at C: blah, blah, blah
> Date:
>
> Apparently, there is a problem accessing the dbm file, though it is there.
> Any help would be greatly appreciated, thanks,
> Tom
>
>
>
>

[Gunnar Hjalmarsson]

Tom wrote:

> I can write to, close aand reopen a dbm file with hashes of hasjed
> of hashes and everything is OK.

No you can't. A simple DBM file only stores keys and values, not
complex data structures.

> Data I write is read back just fine.

Sure. The problem is that what you read is not what you think you
read.

> However, when I run the program again later on and use the same
> exact code to reopen the dbm, al the data is gone.

It was never stored in the DBM file.

> Here is a snippet of what I am doing:
>
> dbmopen (%nd,$ndbfile,0666) || die "Can't dbmopen $ndbfile: $!";
>
> $stk = "ABC";
> $datecode = "20030914";
> $druntime = "700";
> $data = "12345";
>
> $nd{$stk}{$datecode}{$druntime}{Data} = $data;

At this point, you have the hash %nd in memory containing the key
'ABC' and a _hash reference_ as the value. However, the DBM file does
not save the hash reference; it just saves a _string_ that looks
something like 'HASH(0x1555198)'.

<snip>

> Apparently, there is a problem accessing the dbm file, though it is
> there.

No, that's not the problem. (See above.)

--
Gunnar Hjalmarsson
Email: [url]http://www.gunnar.cc/cgi-bin/contact.pl[/url]