#! /usr/bin/perl -w

use strict;
use DBI;
use FindBin;

my $new_total = 10;

open my $fh, '>', $FindBin::Bin . '/data';
print $fh ("DATE,NUMBER\n2005-05-16,2\n2005-05-17,4\n");
close $fh;

my $dbh = DBI->connect('dbi:CSV:f_dir=' . $FindBin::Bin . ";csv_eol=\n")
    or warn "Can't connect to DBI";

my $total = $dbh->selectall_arrayref('select sum(number) from data')->[0][0];
if ($total||0 != $new_total)
{
    require Time::localtime;
    my $lt = Time::localtime::localtime(time();
    my $date = sprintf("%04d-%02d-%02d", $lt->year + 1900, $lt->mon + 1, $lt->mday);
    my $count = $dbh->selectall_arrayref('select count(*) from data where date = ?', {}, $date)->[0][0];
    my $cur = $dbh->selectall_arrayref('select number from data where date = ?', {}, $date);
    $cur = $cur->[0] while $cur and ref $cur;
    my $gained = $new_total - ($total||0);
    if ($count)
    {
        $cur += $gained;
        print "Updating today ($date) to be Number = $cur\n";
        $dbh->do('update data set number = ? where date = ?', {}, $cur, $date);
    }
    else
    {
        $cur = $gained;
        print "Inserting into today to be Number = $cur\n";
        $dbh->do('insert into data (date,number) values(?,?)', {}, $date,$cur);
    }
}

##</code><code>##

DATE,NUMBER
2005-05-16,2
2005-05-17,8

##</code><code>##

DATE,NUMBER
2005-05-16,2
2005-05-17,2005-05-17

##</code><code>##

$ perl -MDBD::CSV -e 'print "perl\t$]\n"; print $_,"\t",${$_."::VERSION"},$/ foreach @ARGV' DBD::CSV SQL::Statement SQL::Parser Text::CSV_XS SQL::Statement::Util
perl    5.008005
DBD::CSV        0.22
SQL::Statement  1.14
SQL::Parser     1.13
Text::CSV_XS    0.23
SQL::Statement::Util    -1, set by base.pm

##</code><code>##

perl	5.008006
DBD::CSV	0.21
SQL::Statement	1.09
SQL::Parser	1.09
Text::CSV_XS	0.23
SQL::Statement::Util