---

2.5.2.3 Linking

   In addition to drag and drop, linking is maintaining a link to the source 
   data. One source can be linked to different target components publishing 
   to these components when its data changes, as shown in Figure 30.  The 
   target components can subscribe to the source to be informed automatically 
   or on request when the data changes.  The following are two ways to update 
   a link (as seen in Figure 31): 

   1.  Automatically 
   2.  Manually 

   If the link is updated automatically, which is the default, then each 
   change of the source data is propagated.  If the link is to be updated 
   manually, then the destination component must initiate the update with the 
   Update now menu option. 


 


                                              



 
   Figure 30. OpenDoc Linking 

   OpenDoc implements a robust object linking mechanism with persistent IDs 
   assigned to objects in order to achieve more reliable linking for both 
   local and remote objects. 


 


                                              



 
   Figure 31. OpenDoc Paste As a Function 

   OLE 2.0 has proven to have fragile links that can break when moving 
   objects, even within the same document.  For instance, OLE references an 
   object via a moniker, which, typically, is a file name (path name) 
   concatenated with a series of item name parts.  If  the file is deleted, 
   renamed or moved, then the link breaks. 

IBM BookManager® BookServer Copyright 1989, 1999 IBM Corporation. All rights reserved.