Using Caché Objects - InterSystems Documentation

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Properties
Properties are the class members that define the state of an object. The manner in which you
can access and manipulate the values of an object's properties depends on the object's class
definition. Formally, there are two kinds of properties:
• Attributes, which hold values
• Relationships, which hold associations between objects
Within Caché, attribute properties are simply referred to as “properties” while relationship
properties are referred to as “relationships.”
Many object languages such as Java and C++ do not have true properties, but rather private
variables manipulated by public accessor methods. In Caché, properties are different than
variables. There is a rich model for properties in which:
• Properties can be literal values, collections of literal values, streams, references to persistent
objects or embedded objects, or collections of references to persistent objects or
embedded objects.
• Properties automatically have a set of property methods supporting validation and storage.
• Properties can transparently invoke sophisticated translations and other advanced functionality
during data retrieval and storage.
• Properties automatically pull embedded and persistent objects into memory as soon as
they are referenced. This is called “swizzling” (sometimes referred to as “lazy loading”
).
Every property has a name, a type, an optional set of modifying keywords, and an optional
set of parameters for its type. A property name must be unique within its class.
Using Caché Objects 45