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You're reading from Documentum Content Management Foundations: EMC Proven Professional Certification Exam E20-120 Study Guide

Product type Book

Published in Jun 2007

Publisher Packt

ISBN-13 9781847192400

Pages 284 pages

Edition 1st Edition

Languages

Concepts

IT Certification

Author (1):

Pawan Kumar

Table of Contents (23) Chapters

Documentum Content Management Foundations

Credits

About the Author

Acknowledgement

About the Reviewers

Preface

1. ECM Basics

2. Working with Content

3. Objects and Types

4. Architecture

5. Users and Privileges

6. Groups and Roles

7. Object Security

8. Searching

9. Custom Types

10. DocApps

11. Workflows

12. Lifecycles

13. Aliases

14. Virtual Documents

Practice Test 1

Practice Test 2

Answers

Chapter 13. Aliases

In this chapter, we will explore the following concepts:

Creating aliases and alias sets
Referencing aliases
Alias resolution

Customization—Reusability and Portability

Documentum customization involves multiple aspects at various architecture layers and these customizations can easily become fairly complex. This complexity can be compounded by the fact that developing and deploying customizations often involves multiple environments — development, QA, and production are typical. Further, multiple departments in an enterprise may have separate repositories of their own.

For example if there are two departments and three environments for each department, it leads to a total of six repositories if a clean separation is maintained. Ideally, customization developed in one repository should be easily ported to all these repositories. This portability is achieved by parameterizing everything that can be different across these repositories such that the parameters specific to a repository...

Customization—Reusability and Portability

The customization artefacts are bundled together in DocApps...

Aliases

An alias is a placeholder name, which needs to be replaced with a value before it can be used. For example, suppose an interviewer needs to be granted certain permissions on a candidate resume, but interviewers can be different for different candidates. In this case, an alias can be created for the interviewer that can be replaced with a real user when the permissions are to be granted to the interviewer.

In a way, an alias acts like a variable in a program that can be specified by a name but whose value is used when the program is run. This allows the developer to create only one permission set and many alias sets rather than many permission sets. Managing a permission set is more complex than managing an alias set. Further, many similar permission sets may become a nightmare to manage when changes may be required for all of them.

In general, an alias can represent a user, a group, a folder location (path in a repository), or a permission set. However, when an alias is stored its...

Alias Sets

Aliases are stored as sets called alias sets. An alias set is stored as an object of type dm_alias_set. The information about each alias is stored in three repeating properties of an alias set, which correspond to each other via identical indices.

Property	Description
`alias_name`	Name of an alias
`alias_value`	Value for the alias, may or may not be present
`alias_category`	Type of alias, various types described earlier

Managing Alias Sets

Alias sets can be created in Documentum Application Builder (DAB), Documentum Administrator (DA), DQL/API queries, or custom DFC applications. The following figure shows an alias set in DA:

Let's now see the same alias set in DAB:

While alias sets can be created and stored unrelated to other objects, they are typically useful only after being associated with one of the following:

Referencing Aliases

When an alias needs to be used as a placeholder its reference is stored using a % prefix. This is a way to distinguish an alias from other values. An alias is referenced as %alias_set_name.alias_name or %alias_name. When the alias set name is omitted from a reference, the alias name is searched for in one or more alias sets according to the alias resolution rules, which are described later. The following figure shows how an alias named interviewer is referenced in another object:

A permission set template (also known as ACL template) is a special type of object that uses aliases. A permission set that contains one or more alias references to users or groups in the r_accessor_name property is known as permission set template. The type of a permission set is identified by the dm_acl.acl_class property, which can have one of the following values:

Object Type	Property	Description
`dm_workflow`	`r_alias_set_id`	Object ID of the alias set used to resolve performer aliases when the workflow is created. It is a run-time copy of the alias set identified in `perf_alias_set_id` of the `dm_process` (workflow template) object.
Session config (non-persistent)	`alias_set`	Session-level default alias set.
`dm_user`	`alias_set_id`	User-level default alias set.
`dm_group`	`alias_set_id`	Group-level default alias set.
`dm_server_config`	`alias_set_id`	System-level (Content Server level) default alias set.
`dm_policy`	`alias_set_ids`...

Resolving Aliases

Aliases provide placeholders for users, groups, locations, and permission sets. When a real value is substituted for a placeholder (alias reference), the alias is said to be resolved. Thus, alias resolution completes the missing information such that the objects and properties dependent on the aliases become available for use.

Alias resolution looks up the appropriate value for an alias name from an alias set. If the alias set name is present in the reference, the process of lookup is straightforward — pick up the value corresponding to the alias name from the specified alias set.

On the other hand, if the alias set name is omitted the Content Server tries to locate an appropriate alias set to look up the alias value. This lookup process utilizes a concept referred to as the scope of alias sets.

An alias scope is the visibility of an alias set for resolving aliases in various situations, including the object using the alias, the context, and the values of other properties...

Help—Some DQL Queries

Some helpful queries related to alias sets are described here. These queries are based on the information provided in this chapter.

The following query retrieves aliases (names, values, and types) present in an alias set:

SELECT alias_name, alias_value, alias_category
FROM dm_alias_set
WHERE object_name = 'my_alias_set'

The following query retrieves the performer names for an activity:

SELECT performer_name
FROM dm_activity
WHERE object_name = 'Screen Resume'

The following query retrieves the accessor names for permission set templates:

SELECT r_object_id, object_name, r_accessor_name
FROM dm_acl
WHERE acl_class=1

Documentum Product Notes

Alias sets can be created in DAB, DA, DQL/API, or a custom DFC application. The Content Server resolves alias references in certain properties of certain types of objects and in the folderSpec argument of link and unlink DFC methods. The custom properties can contain alias references but the Content Server does not resolve them.

ACL templates can only be created in DAB.

Checkpoint

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

1. What are aliases and alias sets? What purpose do they serve?
2. How are alias references used and resolved in various scenarios?

Test Your Understanding

1. An alias set and a permission set are one and the same thing (True/False).
2. A regular permission set does not contain any alias references (True/False).
3. An alias can contain a value of the following type:
a. User
b. Folder path in repository
c. Folder path on the client
d. Permission set name
4. The Content Server resolves aliases for the following properties:
a. dm_acl.performer_name
b. dm_activity.r_accessor_name
c. dm_sysobject.acl_domain
d. dm_sysobject.acl_name
5. It is possible to link an object to a folder, without explicitly identifying the folder by its path or object ID (True/False).
6. The following are valid alias references:
a. %purchasing.manager%
b. %purchasing%.manager
c. %purchasing.manager
d. %manager
7. If a permission set template is applied to four different objects, how many new custom permission sets are created?
a. 0
b. 3
c. 4
d. 5
8. When aliases are resolved for an object with a lifecycle, how many alias sets may be examined?
a. 0
b. 1
c...

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Authors (1)

Pawan Kumar

Pawan Kumar is a Technical Architect with current expertise in Enterprise Content Management with EMC Documentum. He has an MS in Computer Science from University of North Carolina at Chapel Hill and a BS in Electrical Engineering from the Indian Institute of Technology, New Delhi (India). Pawan has experience developing products as well as delivering business solutions on the Documentum platform and has created two products for this platform. He is intimately familiar with effective processes and tools for achieving business objectives through Documentum-based technology solutions. He has led and executed requirements and design workshops, architecture design, scoping, estimation, project planning, resource planning, technical design, software development, software testing, solution roll-out, and ongoing support for the deployed solutions. Pawan has been architecting, designing, and developing enterprise applications for ten years. He has developed software systems for financial services, healthcare, pharmaceutical, logistics, energy services, and retail industries. His expertise spans solution architecture, document management, system integration, web content management, business process management, imaging and input management, and custom application development. Currently, Pawan provides consulting and training services through doQuent (http://doquent.com), which was founded with the vision of enabling client success in content-related business initiatives. He also believes in giving back to the community. He founded the free online Documentum community dm_cram (http://dmcram.org), which is a test preparation resource for Documentum exams. He is also an active contributor to the Documentum-users Yahoo! User group, where Documentum community members seek help for their technical challenges. He can be reached at pk@doquent.com. Contact Pawan Kumar

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