DATA operator

The DATA operator creates a data property.

Syntax

DATA [LOCAL [NESTED [MANAGESESSION | NOMANAGESESSION]]] returnClass [(argumentClass1, ..., argumentClassN)]

Description

The DATA operator creates a data property. This property operator cannot be used inside expressions. The data property can be created local by specifying the keyword LOCAL.

For a local property, you can additionally specify NESTED. In this case, the property becomes nested, and its values are preserved during session-management operations. If no additional modifier is specified after NESTED, the property is treated as nested both when creating a new session and when managing the current session. The MANAGESESSION modifier keeps the nested behavior only for APPLY / CANCEL, while NOMANAGESESSION keeps it only for NEWSESSION.

This operator cannot be used in the JOIN operator (inside [ ]), since a name must be specified for the data property.

Parameters

• LOCAL

  A keyword that, when specified, creates a local data property.

• NESTED

  A keyword that can only be used after LOCAL. It marks the local property as nested. Without additional modifiers, this means that the property is treated as nested both when creating a new session and during APPLY / CANCEL.

• MANAGESESSION | NOMANAGESESSION

  Keywords that can only be used after NESTED.

  • MANAGESESSION means that the property is treated as nested only for operations that manage the current session (APPLY, CANCEL).
  • NOMANAGESESSION means that the property is treated as nested only when entering and leaving NEWSESSION.

• returnClass

  Class ID of the return value of a property.

• argumentClass1, ..., argumentClassN

  A list of class IDs for property arguments. It can be empty; in this case, () is usually used.

Examples

CLASS Item;
quantity = DATA LOCAL INTEGER (Item);

sessionOwners = DATA LOCAL NESTED MANAGESESSION INTEGER ();

CLASS Order;
selected = DATA LOCAL NESTED NOMANAGESESSION BOOLEAN (Order);

CLASS Country;
isDayOff = DATA BOOLEAN (Country, DATE);