Chapter 14. Virtual Documents

In this chapter, we will explore the following concepts:

• Managing virtual documents

• Using virtual documents

Managing Content Hierarchically

The hierarchical content is fairly common in everyday life. A book is an excellent example of hierarchical content. Books are usually organized into chapters, chapters into sections, sections into sub-sections, and there can be more layers in such a hierarchy. A hierarchical organization is frequently used with large content to facilitate its management. While this benefit applies even to content that is not in electronic form, significant benefits are possible for electronic content. This is what the hierarchy for a book looks like:

While the hierarchical organization makes large content manageable, it also opens up new possibilities for online collaboration. For example, suppose a team working on creation of a book consists of two authors, two subject matter reviewers, and one editor. It is highly desirable that all these...

Managing Content Hierarchically

The hierarchical content is fairly common in everyday life. A book is an excellent example of hierarchical content. Books are usually organized into chapters, chapters into sections, sections into sub-sections, and there can be more layers in such a hierarchy. A hierarchical organization is frequently used with large content to facilitate its management. While this benefit applies even to content that is not in electronic form, significant benefits are possible for electronic content. This is what the hierarchy for a book looks like:

While the hierarchical organization makes large content manageable, it also opens up new possibilities for online collaboration. For example, suppose a team working on creation of a book consists of two authors, two subject matter reviewers, and one editor. It is highly desirable that all these participants be able to work on various portions (sometimes even the same portions) of the book in order to complete their tasks efficiently...

Virtual Documents

A virtual document is a container for component documents, which are either simple documents of type dm_sysobject (or a subtype excluding dm_folder and its subtypes) or virtual documents. Even though its primary purpose is to act as a container, a virtual document object can have content of its own.

Note

Note that it is a recursive definition — the definition of virtual document, in turn, uses the term virtual document. In computer science, recursive definitions facilitate description of tree-like structures. We will see in a moment that virtual documents also have a tree structure.

Note that there is no limit on the depth of the hierarchy — a virtual document can contain another virtual document, which can contain another virtual document, and so on. The containment relationship between a virtual document and its component is known as nesting.

The components in the virtual document hierarchy are ordered, which means that there is a sequence among the direct components...

Managing Virtual Documents

Virtual documents can be managed using Webtop. Webtop supports virtual document operations through menu items, the browser-tree component, and the Virtual Document Manager component. Some of the menu options related to virtual documents are shown in the next screenshot:

Creating Virtual Documents

A virtual document is created by converting a simple document to a virtual document. A virtual document is identified by the dm_sysobject.r_is_virtual_doc property being set to 1.

Exploring a Virtual Document Structure

A virtual document is also shown at the folder level in the browser tree within Webtop. This enables browsing of the virtual document components in a way similar to exploring folder contents. Opening a virtual document in Webtop opens it in the Virtual Document Manager component. Let's now see a virtual document open in the Virtual Document Manager interface:

Modifying Virtual Documents

A virtual document can be modified in the following key ways:

1. 1. Add...

Help—Some DQL Queries

DQL provides the keyword IN for checking direct membership of a component in a virtual document. Suppose that the virtual document in the book example has the object ID 0900006480002533. The following query retrieves information about all the chapters and the virtual document itself:

SELECT r_object_id, object_name
FROM dm_sysobject
IN DOCUMENT ID('0900006480002533')
WITH ANY r_version_label = 'CURRENT'

If all the descendants in the hierarchy are desired, the keyword DESCEND can be used after ID().

Further, suppose that books are being represented as a custom type book_doc and stored somewhere in the folder tree under a cabinet named books. The following query retrieves the names of all such books:

SELECT object_name
FROM book_doc
WHERE r_is_virtual_doc = 1
AND FOLDER('/books', DESCEND)

Documentum Product Notes

Webtop supports virtual document preferences for users, as shown:

These preferences specify the default behavior on opening, copying, or checking out a virtual document. Opening a document can mean opening the structure of the document or opening the content of the root virtual document object, if it does have any content. A user may choose one of these alternatives or to be prompted when opening a virtual document.

Similarly, copying a virtual document may mean any of the following:

• Only the root document is to be copied.

• The root document is to be copied along with the links to the existing components.

• All the descendants are also to be copied.

The user may choose one of these alternatives or to be prompted when copying a virtual document.

If the user attempts to check out an item as a part of the virtual document and it is locked by another user, the only options for the user are to cancel the operation or to obtain a read-only copy. The user may specify a preference...

Checkpoint

At this point you should be able to answer the following key questions:

1. 1. What are virtual documents? What purpose do they serve?

2. 2. How are virtual documents created and managed?

3. 3. How do component versions affect virtual documents? What options are available for managing versions with virtual documents?

Test Your Understanding

1. 1. A virtual document enables multiple users to collaborate for creating one document (True/False).

2. 2. A virtual document is stored as an object of the following type:

   a. dm_virtual_doc or its subtype

   b. dm_vdocument or its subtype

   c. dm_sysobject or its subtype

   d. None of the above

3. 3. A virtual document can have objects of the following types as components:

   a. dm_document

   b. dm_folder

   c. Virtual document

   d. None of the above

4. 4. At any time, a document can be a component of:

   a. At most one virtual document

   b. Any number of virtual documents

   c. Any number of virtual documents, as long as they don't share any components

   d. None of the above

5. 5. Components in a virtual document follow these constraints:

   a. All components have the CURRENT version

   b. All components have the same version, but it doesn't have to be current

   c. Each component can have any version independently of the other components.

   d. None of the above

6. 6. Once a snapshot of a virtual document has been created...