A base class is one of twelve standard abstract classes that are immediately below the top class in the hierarchy. This top class, known as the ultimate base class, is identified by the symbol @baseclass.

The three base classes of greatest interest to application developers are Data-, Assign- and Work-. The base classes are:

Base class	Description
Assign-	Assignment instances, each identifying a step in a workflow that requires human input or work by an outside organization, person, or system.
Code-	Classes that directly reference server program code. Pages belonging to classes derived from the Code- base class exist only temporarily in memory, and are not saved in the PegaRULES database.
Data-	Parent class of concrete classes containing reference data, including data for system administration and security.
DCOMSOffice-	Reserved.
DocletGenerator-	Reserved.
Embed-	Defines the structure of pages embedded within other pages. Pages belonging to classes derived from the Embed- base class cannot be renamed or directly saved.
History-	Append-only instances record the change history of objects in another class.
Index-	Secondary access keys defined to provide fast retrieval of other instances.
Link-	Instances that record associations between two objects.
Log-	Parent of concrete classes containing cumulative logs of important system-wide events.
Pega-	Support internal functions of the Designer Studio.
PegaAccel-	Parent of special classes that support the Application Accelerator tool.
Rule-	Rule types, for defining applications.
System-	Contains operational status information about the entire Process Commander system.
Work-	Work objects, covers, and folders.

Custom classes that are immediate child classes of the ultimate base class are known as top-level classes. These are different from base classes.

	abstract class, class, concrete class, embedded page, inheritance, top-level class, ultimate base class
	About Class rules Using the Class Explorer
	Atlas — Standard class rules

Definitions — B