Borland originally introduced its multitier technology in Delphi 3 and has kept extending it from version to version. In addition to further updates and the change of the MIDAS name to DataSnap, Delphi 6 saw the introduction of SOAP support, introducing an alternate and extended architecture for multitier applications. We'll fully explore this topic in Chapter 23. Delphi 7, on the other hand, cut back on CORBA support.
However, with the introduction of a new licensing scheme (basically, free deployment), Delphi 7 has paved the way for increased adoption of this technology. This is particularly true of DataSnap's SOAP variant, but socket connections also provide a very good balance of data transfer efficiency and ease of deployment.
For the moment, we'll continue with database programming, discussing data-aware controls and custom datasets. In the final part of the book we'll explore sockets, Internet programming, and SOAP, so you'll have a complete picture of possible multitier architectures based on Delphi—not to mention the availability of third-party tools providing features similar to DataSnap.