A concrete class can have instances stored in the database. In contrast, an abstract class cannot have any instances.

A selection on the Class form determines whether a class is concrete or abstract. On the Class Explorer display, the shape identifies a concrete class.

For all but a few classes, a dash or minus sign (-) character as the last character in the class name indicates that the class is abstract and can contain other (abstract or concrete) classes. For example, the Rule- class and Work-Cover- class are abstract classes, while Work-Cover-General is a concrete class.

Concrete classes usually appear near or at the bottom (leaf nodes) of the class hierarchy, but may appear anywhere below the top level.

	abstract class, base class, class, directed inheritance, ultimate base class
	About Class rules  Class hierarchy — Concepts and terms

Definitions — C