A CMS-based web site can be presented with four logical levels. The data level defines the infrastructure of incoming content. The functional level describes the models of interactions between groups of users and data presentation interfaces. The presentation level is a mature user interface that enables delivery of the requested media data to the Internet/Intranet users. The management level is an interface of CMS administrative area; it allows users to manage data, functionality and presentation levels.

Figure 2. Four-level model of a managed site

3.6.1.1 Data Level

The infrastructure of the data arriving at the site can have various implementations. However, SAPI contains guidelines on using the query containers (see section Query Container: Element SAPI:QC), defining the management interface by the content provided in the CMS administrative area. When saying that the CMS is used in the site administration mode, the administrative level or the administrative area is implied.

3.6.1.2 Functional Level

The functional level of a site is described in the SAPI document.

3.6.1.3 Presentational Level

This document describes the following presentation model:

When displaying any part of the site, according to the parameters of the requested document (URI), CMS determines the environment variables compatible with the SAPI specification. Then the system identifier of the requested site document and its related definition are determined, including the pointers to the document presentation template and the SAPI document. These parameters are transferred to the SAPI parser for generation of the site document presentation. The CMS mode in the process of visitors looking through the site implies the presentation level or the presentation area.

Figure 3. Model of the data presentation process