I know that I have sought your advice on this before, but I'm still kinda stuck with this problem. I have a program which takes a structured format file and reports back data contained in specified fields. I am writing a program which will "join" the output of 2such files. I have gathered from all of you that my best bet would be to use a relational database. So, armed with DBI, DBD::CSV, etc and my new "Programming the Perl DBI" book, I am off to tackle this once again. First, let me demonstrate what I am trying to accomplish. eg: exfields.pl file1.gz name,ipAdd,DestDev which produces the following output: 
"atlanta"    "192.168.1.1"    "vienna"
"miami"      "192.168.1.2"    "dallas"
"nyc4"       "192.168.1.3"    "boston"

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As you can see, "name,ipAdd,DestDev" are names of structured fields within the gzipped file. Let's say I ran this: 
exfields.pl file2.gz name,ifSpeed

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which produces the following output: 
    
"atlanta"        "622000000"
"miami"          "155000000"
"nyc4"           "155000000"

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my new program would "merge" the output of both of those files producing: 
"atlanta"  "192.168.1.1"  "vienna"  "622000000"
"miami"    "192.168.1.2"  "dallas"  "155000000"
"nyc4"     "192.168.1.3"  "boston"  "155000000"

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So, here's what I've got so far: 
#!/usr/local/bin/perl -w

## merge.pl

use strict;

if ($ARGV[3] ne "") {
    my $file1 = $ARGV[0];
    my $list1 = join (",", $ARGV[1]);
    my $file2  = $ARGV[2];
    my $list2 = join (",", $ARGV[3]);


    my %hash_1  = process($file1, $list1);
    my %hash_2  = process($file2, $list2);
  
}else {
    print "merge.pl - Usage: file field(s) file field(s)\n";
}

sub process {
    my ($file, $list) = @_;
    my $script = "perl /home/limo/Perl/exfields.pl -e"; 
    my %hash;
    my $arg;
    
      for $arg (split /,/ => $list) {
    open(FILE, "$script $arg $file |") or die "System error: $!\n";
    while (<FILE>) { 
        next if /^(#|none|unkno)/i;
        chomp;     
        push @{ $hash{$arg} }, split;
    }
    close FILE;
    }
   
    return %hash;
}

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I suppose that I have three questions: 1. It was sugessted that I return a reference to a hash, thus conserving some memory. Would that just be, return /%hash? 2. In any case, what kind of print statement can I insert to test the contents of each hash, as returned? 3. I can't seem to find any information regarding reading data contained in a hash into DBI? Oh yeah, the reason that I am using a hash is that I would like the keys of the hash to become the column headers in the database table that I create. Any direction/help, as always, is much appreciated!

In reply to Data in Hash - DBI by Limo

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