State Management in WWW Database Applications

Nowadays, the WWW is believed to be the ideal technological platform for the introduction of online telematic applications as well as information systems in enterprise intranets due to its wide acceptance and standardisation (W3C). In the majority of cases, the databases supporting such novel applications are hosted by RDBMSs. This paper touches upon the incompatible nature of WWW compliant database applications and classical database applications (developed with Embedded SQL/3GLs, 4GLs, etc.). The WWW is often blamed for the stateless character of one of its constituents; the HyperText Transfer Protocol (HTTP). The so-called “user session” concept is not applicable in its client/server architecture. Communication between clients and servers is realised by means of fairly simple request-response interactions (“hits”) which are treated independently (without memory state) by servers. We propose an architecture for the deployment of stateful database applications in the context of conventional WWW servers. In this architecture, state information preserved in the WWW client as well as in specialised agents that operate behind the WWW server, provides the required basis for a “session-aware” database application. The main benefits of this architecture are that it doesn’t modify existing server software and requires minimum programming effort for the porting of existing “session-aware” applications to the WWW environment.