using com.apama.dataview.DataViewUpdateItem;
...
string location;
integer temp;
integer humidity;
integer visibility;
...
DataViewUpdateItem update := new DataViewUpdateItem;
update.dvName := "Weather";
update.dvItemId := -1; // Set the ID to -1 when using keyFields
update.fieldValues :=
   [location,temp.toString(),humidity.toString(),visibility.toString()];
route update;