C++Builder 5 Developers Guide

In this chapter, you looked at Borland's multitier technology called DataSnap. In particular, you saw how to create servers and clients and how to use DCOM, sockets, and HTTP to connect to a remote server.

This technology is important for several reasons:

• It provides a means of creating thin clients that make few demands on the client system.

• It simplifies ”in fact, nearly eliminates ”the need to configure the client machine.

• It enables you to partition applications in logical compartments. If you want, each of these compartments can be run on a separate machine, thereby distributing the load of the application.

• It provides a means for distributing a load over several server machines or for routing the load to a specific machine with the power to handle heavy demands.

• It provides a robust architecture for handling and reporting (reconciliation) errors, particularly in a multiuser environment.

• It enables you to use a briefcase technology that stores files locally and allows you to reload them when it is time to update the server. This capability is ideal for laptop users who spend a lot of time on the road.

For many users, this technology is so compelling that it entirely replaces the standard client/server database architectures. These users are attracted to the capability to partition an application into logical pieces, even if the entire application is being run on a single machine. However, the biggest benefits achieved by this architecture become apparent when you bring multiple machines and servers into play.

This chapter should get you started using some of the more sophisticated aspects of this technology. There will come a time when nearly every computer in the world will be continually connected to nearly every other computer. When that occurs, distributed computing will become one of the most essential fields of study in computer programming. DataSnap is a very helpful piece of technology in this respect.

The next chapter will focus on the different connection components and communication protocols. Including the use of Web services as DataSnap servers.