Delta Links 

Definition

A delta link is a relationship between two objects in the Portal Content Directory that is established when one object (the target object) is based on another object (the source object). The source object passes its property values to target objects that have been derived from the source object. Changes made to the source object are copied to the target object and are visible there. Changes made to the target object have no effect on the source object. For more information, see Inheritance of Properties.

The delta link operates on hierarchies and property values of objects.

The main advantage of this concept is that objects can be reused or changed without changing the original or source object. You can make changes to delta link objects (target objects), such as deleting or adding entries in role hierarchies or changing property values for iViews and pages, without having to change the source object.

With the delta link concept, you can protect your own objects and the content objects shipped by SAP and other vendors against modifications. See also Delta Links and SAP Content Objects and Creating Delta Links.

Creating Chained Objects

Using delta links, you can create chained objects where an object can be both the source and the target object, depending on its position in the chain.

The following diagram shows an iView (iView 1) that is created in the Portal Catalog with a delta link and then added to page X as a delta link. Page X is then added to workset Y as a delta link and workset Y is added to role Z as a delta link.

iView 1 is the target object that is derived from the source object iView template in the Portal Catalog. iView 1 is also the source object for iView 1, which is contained in page X as a delta link.

Nearly all the objects of the Portal Content Directory (PCD) are linked to other objects with a delta link; that is they always reference other objects. Only the objects at the top location of an object inheritance chain are not delta links. In this case the objects are master objects, from which other objects are derived. They themselves have no source object that they reference.

You can display the position of an object within the object chain. For more information, see Tracing Delta Link Dependencies.