Change operators
Change operators - a set of operators that determine various types of property value changes.
Syntax
typeChange(propExpr)
Description
Change operators create actions which determine whether some types of changes have been made for a certain property in the current session.
Parameters
-
typeChange
Type of the change operator. It is specified by one of the keywords:
SET
CHANGED
DROPPED
SETCHANGED
DROPCHANGED
SETDROPPED
-
propExpr
An expression which value defines the property that should be checked for the presence of a change.
Examples
quantity = DATA NUMERIC[14,2] (OrderDetail);
price = DATA NUMERIC[14,2] (OrderDetail);
sum(OrderDetail d) <- quantity(d) * price(d) WHEN CHANGED(quantity(d)) OR CHANGED(price(d));
createdUser = DATA CustomUser (Order);
createdUser (Order o) <- currentUser() WHEN SET(o IS Order);
numerator = DATA Numerator (Order);
number = DATA STRING[28] (Order);
series = DATA BPSTRING[2] (Order);
WHEN SETCHANGED(numerator(Order o)) AND
NOT CHANGED(number(o)) AND
NOT CHANGED(series(o))
DO {
number(o) <- curStringValue(numerator(o));
series(o) <- series(numerator(o));
incrementValueSession(numerator(o));
}
;