An Intelligent SQL Tutor on the Web
13 (2): "Part II of the Special Issue on Adaptive and Intelligent Web-Based Systems "
The paper presents SQLT-Web, a Web-enabled intelligent tutoring system for the SQL
database language. SQLT-Web is a Web-enabled version of an earlier, standalone ITS. In this paper we
describe how the components of the standalone system were reused to develop the Web-enabled system.
The system observes students' actions and adapts to their knowledge and learning abilities. We describe
the system's architecture in comparison to the architectures of other existing Web-enabled tutors. All
tutoring functions are performed on the server side, and we explain how SQLT-Web deals with multiple
students. The system has been open to outside users since March 2000. SQLT-Web has been evaluated in
the context of genuine teaching activities. We present the results of three evaluation studies with the
University of Canterbury students taking database courses, which show that SQLT-Web is an effective
system. The students have found the system a valuable asset to their learning.
Keywords. Web-based ITS, architectures for adaptive and intelligent Web-based educational systems,
intelligent problem solving support via the Web, student modelling and student model servers in the Web
context, empirical studies of Web-based adaptive and intelligent educational systems.
Intelligent Tutoring Systems (ITS) offer the advantage of individualized instruction without the
expense of one-to-one human tutoring. Although numerous ITSs have been developed to date,
they are mostly used in research environments, and only a few have been used by large numbers
of students in real classrooms. The main cause of such limited use of existing systems is the
complexity of ITS development, and the difficulties with providing robust and flexible systems.
Despite the fact the area is not young, there are no well-established methodologies or
development tools. Furthermore, the hardware platforms available in most schools are not the
ones developers prefer, and porting systems between platforms is in no way a straightforward
task. Fortunately, Web-enabled versions of ITSs have the potential to reach a much wider
audience as they face significantly fewer problems with hardware and software requirements.
We have developed SQL-Tutor, a standalone system for teaching SQL (Structured Query
Language) (Mitrovic, 1998a). The system has been used by senior computer science students at
the University of Canterbury and has been found easy to use, effective and enjoyable (Mitrovic
& Ohlsson, 1999). The system has been developed in Allegro Common Lisp (Allegro, 1998) and
is available on MS Windows and Solaris. Besides local users, two thousand people worldwide