Lecture 8. Ingres: general organization of the system, Quel language basics

8.1. Ingres DBMS History

In terms of importance for the development and dissemination of the relational approach to database management, Ingres (Interactive Graphics and Retrieval System) DBMS is close to System R, although the history and organization of this system differs in many ways from System R. First, let's briefly review the history of Ingres.

The project and the experimental version of Ingres DBMS were developed at the University of Berkeley under the guidance of one of the world's most famous database scientists and experts Michael Stonebraker. From the very beginning, Ingres DBMS was developed as a mobile system operating in the UNIX environment. The first version of Ingres was designed for 16-bit computers and worked mainly on PDP machines. It was the first DBMS distributed free of charge for use in universities. Subsequently, the Stonebreaker group moved Ingres to UNIX BSD, which was also developed at the University of Berkeley. The Ingres DBMS family at the University of Berkeley is commonly called the "university Ingres".

In the early 1980s, RTI (Relational Technology Inc.) was formed to bring university prototypes to the level of commercial products. From this point on, the university and commercial Ingres DBMS were distinguished. Currently, commercial Ingres is maintained, developed and sold by Computer Associates. Now it is one of the developed commercial relational DBMS.

Although in many ways the commercial options for Ingres are more advanced than university ones, for educational purposes it is much more interesting to talk about university developments. Firstly, as in the case of any commercial product, information on the internal organization of commercial Ingres is mainly confidential. At the same time, there are many high-quality publications about university Ingres. Secondly, the university Ingres can be tested in practice and even see its source code. Finally, thirdly, it was in the university Ingres that many original ideas were used that are currently used in many other systems. With the use of this system, many academic and research work was carried out at the University of Berkeley (and other universities).

Therefore, in this lecture, we will consider the organization of the university version of Ingres DBMS, which is closely related to the features of the QUEL language (to the same extent that System R is closely related to the features of the SQL language). Further, when speaking about the Ingres DBMS, we will refer to the university Ingres in this lecture.