docs: public String getPrimaryKeysString() {
  
          String result = "";
  
          for (int i = 0; i < primaryKeys.length; i++) {
              if (result != "") {
                  result += ", ";
              }
  
              result += primaryKeys[i];
          }    // end of for (int i=0; i<primaryKeys.length; i++)
  
          return result;
      }