i%PropertyName (Instance Variables)

i%PropertyName (Instance Variables)

This section introduces instance variables. You do not need to refer to these variables unless you override an accessor method for a property; see Using and Overriding Property Methods.

When you create an instance of any class, the system creates an instance variable for each non-calculated property of that class. The instance variable holds the value of the property. For the property PropName, the instance variable is named i%PropName, and this variable name is case-sensitive. These variables are available within any instance method of the class.

For example, if a class has the properties Name and DOB, then the instance variables i%Name and i%DOB are available within any instance method of the class.

Internally, InterSystems IRIS also uses additional instance variables with names such as r%PropName and m%PropName, but these are not supported for direct use.

Instance variables have process-private, in-memory storage allocated for them. Note that these variables are not held in the local variable symbol table and are not affected by the Kill command.