For many years, OracleAS Forms Services has been one of the most popular 4GL development environments for Oracle database applications. OracleAS Forms Services was designed originally to be closely integrated with the Oracle database. As we mentioned, OracleAS Forms Services uses PL/SQL as the language for its extended logic. The same Oracle sales team that provided the Oracle database was also able to helpfully supply this development tool. But, as the technology environment evolved, OracleAS Forms Services was caught in a bind. Like many client-server tools, OracleAS Forms Services split the runtime functionality of its applications between the client and the server.
The new environment of Internet computing required a slightly different deployment model. To address this new requirement, the OracleAS Forms Services development team created a new deployment model in 1997 with Release 4.1. In this new model, a Java applet talks to a Java servlet on a server. That server, in turn, calls the OracleAS Forms Services runtime. With this new deployment model, OracleAS Forms Services deployment was transformed from a two-tier client-server architecture into a three-tier web-based architecture.
The interaction between a web client and an Oracle Forms application through OracleAS Forms Services is shown in simplified form in Figure 9-1.
Figure 9-1. Simplified ...