#!/usr/bin/perl -w
use strict;

use DBI;   ## need to have DBD::CSV installed for this script!

my $dbh = DBI->connect ("DBI:CSV:", undef, undef,  # no uname, pwd
    {
        f_dir        => './',   # default current directory
        f_ext        => ".csv", # DB files end in .csv
        csv_eol      => "\n",   # default (used for writing)
        csv_sep_char => ',',    # default of course is comma!
        RaiseError   => 1,      # errors are fatal (with description)
        PrintError   => 0,      # default is 0 not needed if RaiseError=1
                                #   non-zero prints error and continues
    }
) or die "Cannot connect: " . $DBI::errstr;

my $st_basic_actions = $dbh->prepare("SELECT action,userID,Place
                        FROM DataBase
                        ORDER BY userID");
$st_basic_actions->execute();

printf "%-10s %-10s %-10s\n", 'Action','userID','Place';  
while (my ($action,$userID,$Place) = $st_basic_actions->fetchrow)
{
   $Place ||= 'unknown';  # use 'unknown' if null string, ''
   printf "%-10s %-10s %-10s\n", $action,$userID,$Place
}
=outputs  ################
Action     userID     Place     
G          CHXAS      unknown   
X          LLXEAS     Wah Woo, Section A
X          LLXEAS2    Wah Woo, Section A
=cut      ################

my $st = $dbh->prepare ("SELECT * FROM DataBase");
$st->execute();

while (my $href = $st->fetchrow_hashref())
{
   print "****\n";
   foreach my $key (sort keys %$href)
   {
      print "$key=$href->{$key}\n" if $href->{$key}; 
   }
}
=outputs ###############
****
action=X
dept2=DSA
first_name=Lamshi
footer=Welcome to Coo Duk, ltd.
nameid=LLXEAS2
oxcode=A
pc=HKA
place=Wah Woo, Section A
section=CWW
state=Important
status=NAW
subject=No vell
surname=Coo
userid=LLXEAS2
****
action=X
dept2=DSA
first_name=Lamshi
footer=Welcome to Coo Duk, ltd.
nameid=LLXEAS
oxcode=A
pc=HKA
place=Wah Woo, Section A
section=CWW
state=Important
status=NAW
subject=No vell
surname=Coo
userid=LLXEAS
****
action=G
second_mail_alias=sam.mo@hotmail.com
userid=CHXAS
=cut

# **CODE UPDATE**: adding an "update" to show modification is possible

$st = $dbh->prepare ("UPDATE DataBase 
                      SET action='Done' 
                      WHERE userID='LLXEAS2'");
my $rows_modified = $st->execute();
print "\nRows Modified from X to Done = $rows_modified\n";

## now re-running previous query, can re-use a prepared statement
## handle 

$st_basic_actions->execute();

printf "%-10s %-10s %-10s\n", 'Action','userID','Place';  
while (my ($action,$userID,$Place) = $st_basic_actions->fetchrow)
{
   $Place ||= 'unknown';  # use 'unknown' if null string, ''
   printf "%-10s %-10s %-10s\n", $action,$userID,$Place
}

##########################
=this new section of code prints:

Rows Modified from X to Done = 1
Action     userID     Place     
G          CHXAS      unknown   
X          LLXEAS     Wah Woo, Section A
Done       LLXEAS2    Wah Woo, Section A

=cut
############################