#!/usr/bin/perl -wT

use strict;
use DBI;

#Global Database Connection string, set in Apache's httpd.conf
$ENV{DBI_DSN} ||= 'DBI:mysql(RaiseError=>1,ChopBlanks=>1,Taint=>1,AutoCommit=>1):;mysql_read_default_file=/etc/.my.cnf;database=MyDB';

my $statement = q{
  SELECT *
    FROM table
   WHERE column = ?
};

my @bind_values = qw(value);

my $dbh = DBI->connect;
my $sth = $dbh->prepare($statement);

if(checksums($sth, \@bind_values)) {
  my $results = computation($sth, \@bind_values);

  #do something with the $results
}

$dbh->disconnect;

sub checksums {
  my $sth         = shift;
  my $bind_values = shift;

  $sth->execute( @$bind_values );
  my $results = $sth->fetchall_arrayref({});

  #validate the $results

  return 1;
}

sub computation {
  my $sth         = shift;
  my $bind_values = shift;

  $sth->execute( @$bind_values );
  my $results = $sth->fetchall_arrayref({});

  #perform computation on the $results

  return $results;
}