Documentum Content Management Foundations: EMC Proven Professional Certification Exam E20-120 Study Guide: Learn the technical fundamentals of the EMC Documentum platform while effectively preparing for the E20-120 exam

Databases are ubiquitous in modern technology solutions. This is a mature field and well-known best practices are routinely used for deploying databases. Databases provide standard means for accessing and manipulating structured data. Structured means that the data components (fields) are of specific type (integer, string, etc.) and this knowledge helps in querying and manipulating the data.

On the other hand, files stored on the file system are generally unstructured and can contain information in any form. Such files and the unstructured information contained therein are collectively referred to as content.

While databases provide standard means of managing structured data, content management systems (CMS) are a relatively new phenomenon. Since the content itself is unstructured, it is not possible to read and understand the content without any prior knowledge about it. Therefore, some structured data is attached to each content item, which describes the content item. This data that provides information about the attached content item is called metadata.

Content management systems utilize metadata extensively to provide sophisticated functionality. For example, metadata is essential for making documents searchable in terms of their author, title, subject, or keywords. It is hard to imagine any functionality of Documentum that does not utilize metadata in one form or another. The following figure shows two content items and their associated metadata:

Content management systems need to manage both content and metadata. EMC Documentum uses the host file system (by default) to store the content and a database to manage metadata and its association with the content items. Note that the content can also be stored in other types of storage systems, including a Relational Dababase Management System (RDBMS), a content-addressed storage (CAS), or external storage devices.

A repository is a managed unit of content and metadata storage and includes areas on the file system and a database. However, the details of the organization of the files and metadata in a repository are hidden from the users and applications that need to interact with the repository. The repository is managed and made available to the users and applications via standard interfaces by a Content Server process. The following figure shows the basic structure of a repository:

The repository was known as docbase in pre-5.3 versions of the Documentum platform. These two terms are used interchangeably by the Documentum community.

Content Server serves content to applications, which in turn provide friendly interfaces to human users. Content Server brings the stored content and metadata to life and manages its lifecycle. It exposes a known interface for using the content while hiding the details of how and where files and metadata are stored.

The term Content Server is used in two contexts — the Content Server software that is installed and resides on the file system and the Content Server instance, which is the running process that resides in memory and serves content at run time. However, there is little chance of confusion since the usage is often clear from the context and the term Content Server is typically used without additional qualification (software or process/instance).

A Content Server instance is dedicated to and manages only one repository. However, we will see later in architecture discussion that multiple Content Server instances can be dedicated to the same repository. This is typically done for performance reasons where the multiple Content Server processes divide up the load for serving content from the same repository. The following figure shows two Content Servers serving one repository:

Content Server is the foundation of the Documentum platform and provides the following services:

These features are described here briefly and in more detail in later chapters.

Distributed Services

A Documentum installation can include multiple repositories and the Content Server is aware of distributed configurations that deployments can take.

The Content Server provides an application programming interface (API) and therefore needs a layer in front of it to expose its capabilities to human users. Documentum provides desktop and web-based client applications and supports creation of custom applications of either type. The following figure shows several client applications:

The full set of Content Server features is exposed via Documentum Foundation Classes (DFC) and Documentum Client Library (DMCL). DFC provides the API for interacting with the Content Server programmatically.

Documentum also provides a Web Development Kit (WDK) to facilitate development and customization of web-based client applications.

Documentum provides two interactive utilities for interacting with the Content Server using queries — IDQL and IAPI. These utilities are typically used by administrators and developers.

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