I put something like this in my instance script (and maybe in my application models, also):

use CGI::Carp  qw(fatalsToBrowser set_message);
BEGIN {
 set_message( sub {
   my $msg = shift;

   # message for development server
   #print "<h3>Server Error!</h3><pre>$msg</pre>";

   # message for production server
   print "<h3>Server Error!</h3><p>Please try again later</p>";

 });
}
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Then I wrap all my database stuff with eval:

  eval {
    $db1 = DBI->connect(
      $CFG{'DB_DSN'},
      $CFG{'DB_USER'},
      $CFG{'DB_PASS'},
      {RaiseError => 1, AutoCommit => 1, },
    );
  };

  if ($@) {
    die "Database error: failed to connect.\n";
  }
[download]

This basically allows me to trap any DB related errors, and avoid sending too much information to the browser, unless I'm in "debug mode".