Typical DataSnap Architecture
Figure 21.3 shows how a typical DataSnap application looks after it's created. At the heart of this diagram is a Data Module constructed for this task. Several varieties are available. For simplicity, we'll use a COM-based one in this chapter, called the Remote Data Module (RDM). The RDM is a descendant of the classic data module available since Delphi 2. This data module is a special container that only allows non-visual components to be placed on it. The RDM is no different in this respect. In addition, the RDM is actually a COM object—or to be more precise, an Automation object. Services that you export from this RDM will be available for use on client machines.
Figure 21.3. A typical DataSnap application.