Coupling ORACLE with ECLiPSe

We describe the design and implementation of an interface between a Prolog system, ECLiPSe, and the relational database management system, Oracle. ECLiPSe is used to solve sophisticated planning and scheduling problems and sometimes needs to access data stored in a legacy system to do this. A typical ECLiPSe application would be job shop scheduling and a legacy system might be used to store the orders that have to be scheduled by the system. The interface, called CORE, enables the writer of the ECLiPSe application to query the database for both the whole set of answers and tuple-at-a-time. We also describe the use of the interface in an application demonstrator for generating lecture timetables at Imperial College. 1 Motivation The aim of this paper is to explain the requirement for and design of an interface between the Prolog system, ECLiPSe, and the relational database, Oracle. ECLiPSe is used to solve sophisticated planning and scheduling problems and sometimes needs to access data stored in a legacy system such as Oracle. The interface to be presented here enables the developer of the ECLiPSe application to query the database for both tuple-at-a-time and the whole set of answers. This work was carried out on the DTI/EPSRC funded research and development project CHRONOS and was targeted towards writing application demonstrators for real problems. One of the the applications used in the project was an application from Imperial College itself which is described below in detail. The ECLiPSe language is typically used in applications which solve planning and scheduling problems. In the CHRONOS project our focus was on applying it to resource allocation problems, for instance allocating classrooms within lecture timetables. Our task was to write an application that did lecture and tutorial timetabling for departments at Imperial College. Each department has its own lecture rooms which can seat a certain number of students and have various available facilities, such as overhead projectors, videos or computers. Lecturers request a classroom with a certain capacity and facilities and they may also have preferences as to the time of the class. The application program will attempt to timetable the lectures and tutorials. The program takes into account factors such as making sure that the lecture room is large enough for the number of students and tries to take account of individual lecturer's preferences, for example, the lecturer may particularly dislike giving lectures before 10am. 1 The data about …