The Unified API applies to three functional areas:

Each area is accessible through a repository. A repository provides access to persistent objects and offers various services. Many tasks can be performed while only accessing a single repository, but at times you need access to the full functionality. For each repository, you will find in the following an entire chapter containing a detailed discussion. This chapter, however, is limited to topics that apply regardless of the repository at hand.

First, the connection object is discussed. It mediates between the individual repositories. Because the connection is the primary entry point when working with the Unified API, it is explained in detail how a connection can be obtained and configured.

Then, key concepts are described that apply equally to all three repositories. The basic structure of all repositories is essentially the same and also the persistent objects share many features. Moreover, one should be aware of certain design principles that apply throughout the Unified API.