my $oldrow;
my(@fields,@values);
while(<DATA>) {
  chomp;
  my ($row,$col,$data) = /^\s*\(\s*(\d+)\s*,\s*(\d+)\s*\)\s*=>(.*)$/;
  # that puts the row number in $1, col number in $2 and data in $3, and in the variable respectively
  if($oldrow != $row) {
    if(@fields) { #make sure there is data
      $query = "INSERT INTO tablename(".(join ',', @fields)." VALUES(".(join ',', @values).')';
      ... do DB calls ...
      @fields = @values = ();
    }
    $oldrow = $row;
  }
  push @fields, $field_names[$col]; # field name with proper data
  push @values, db->quote($data); #run data through DB quoter
}