Using Caché Objects - InterSystems Documentation

Properties
7.5 Attribute Properties
An attribute property is a value associated with a specific object (as opposed to a relationship
property which relates two or more objects). Such properties typically represent the state of
a specific object instance.
A property's type is determined by the class associated with the property (or by a keyword
in the case of collection and multidimensional properties). By default, properties use the
%String data type.
There are several types of attribute properties, including:
• Data Type Properties
• Object-Valued Properties
• Collection Properties
• Stream Properties
• Multidimensional properties
7.5.1 Data Type Properties
The simplest type of property is a data type property. This is a literal value whose behavior
is controlled by the data type class associated with the property.
For example, a class can define a Count property using the %Integer data type:
Property Count As %Integer;
Since %Integer is a data type class, Count is a data type property.
You can use data type parameters to place constraints on the allowed values of data type
properties. You can specify values for the data type class parameter as follows:
Property Count As %Integer(MAXVAL = 100);
To set a data type property value equal to the empty string, use code of the form:
Set object.Property = $C(0)
50 Using Caché Objects