Building Controls Software around an Object-Oriented Database

The use of Object-Oriented (OO) techniques has become popular in all areas of software technology and HEP control systems have not been excluded from this trend. In the course of modernisation of the CERN SPS Experimental Areas control software we designed and implemented an OO database to hold the configuration data for equipment and beams. With the beam lines and equipment defined in the new database, control facilities are being added by incrementally enhancing the classes and adding new methods to the database schema. Using the OO database helps to design the new system in a transparent way. Real-world objects such as beam lines or crates are uniquely mapped to the corresponding objects in the database. The new database allows seamless integration of data into programs written in OO languages such as C++ and Java. The WWW interface to the database gives a familiar look and feel and has been provided with relatively little effort. In this paper we present an overview of the project and the employed methods. The choice of the database management system, the implementation of the Beam Instrumentation (BI) database and its use in controls as well as the benefits of the approach will be discussed in some detail.