Using Caché Objects - InterSystems Documentation

Class Queries
If the query takes runtime parameters, they appear on the method argument list after the query
handle. For example, if the ByName query takes a name parameter, its signature is:
ClassMethod ByNameExecute(ByRef qHandle As %Binary, Name As %String)
As %Status
{
// query setup code here
Quit $$$OK
}
8.2.2 The querynameFetch Method
The querynameFetch method fetches a single row of data and formats it into $List format.
(If it is unable to fetch a row, it returns "" in lieu of data.)
If you create the query using the Wizard, it creates a method signature for you. The significant
elements of this signature are:
• The method's first argument, the qHandle variable, is of type %Binary, is defined in
querynameExecute, and is passed by reference.
• The method's second argument, the Row variable, is either a %List of column values
representing the current row being returned and "" if no row is returned. It is passed by
reference.
• The method's third argument, the AtEnd variable, is of type %Integer and indicates that
subsequent calls will not return a valid row. It is passed by reference.
• The method returns status information in a variable of type %Status.
8.2.2.1 The First Argument — The qHandle Variable
The first argument of a querynameFetch method is of type %Binary, is called qHandle, and
is passed by reference. It contains all information from querynameExecute needed by
querynameFetch and passes information from both methods to querynameClose.
8.2.2.2 The Second Argument — The Row Variable
The second argument of a querynameFetch method is of type %List, is called Row, and is
passed by reference. If the querynameFetch method can retrieve the next row's data, it sets
the row data variable to a list containing the active row's data. The value of each field is a
single element in that list. If no more rows can be returned (that is, the query has reached the
end of the rows), then the variable is set to "".
60 Using Caché Objects