# update a database entry with a new version of a file:
     my $size = -s $file;
     # first we need to find the CS_IODESC data for the data
     $sth = $dbh->prepare("select img from imgtable where id = 1");
     $sth->execute;
     while($sth->fetch) {    # don't care about the data!
         $sth->func('CS_GET', 1, 'ct_data_info');
     }

     # OK - we have the CS_IODESC values, so do the update:
     $sth->func('ct_prepare_send');
     # Set the size of the new data item (that we are inserting), and make
     # the operation unlogged
     $sth->func('CS_SET', 1, {total_txtlen => $size, log_on_update => 0}, 'ct_data_info');

     # open the file, and store it in the db in 1024 byte chunks.
    open(IN, $file) || die "Can't open $file: $!";
    while($size) {
        $to_read = $size > 1024 ? 1024 : $size;
        $bytesread = read(IN, $buff, $to_read);
        $size -= $bytesread;

        $sth->func($buff, $bytesread, 'ct_send_data');
    }
    close(IN);
    # commit the operation
    $sth->func('ct_finish_send');