Question about mysql-d Object

[Martin Tschierschke via Digitalmars-d-learn]

When I do the following:

auto mysql = new Mysql("localhost", 3306, "mt", "", "verwaltung");
auto rows = mysql.query("select field from my_table limit 50");

foreach(row;rows){
  writeln(row["field"]);}

// second time same loop

foreach(row;rows){
  writeln(row["field"]);}

I only get the output of the first loop (50 lines), probably this 
is a feature
not a bug, but what kind of Object is rows?

A nested loop, did not worked either:

foreach(row;rows){
  foreach(field;row){
  writeln(field);}
}

Which other ways to access the elements of rows do I have?

Sorry, but I am very new on D, (it may be the best language 
available, I don't know yet, but it is really the most 
interesting!) thank you!