The paper written by Donald Chamberlin et. al. under IBM Research Lab entitled “A History and Evaluation of System R” was published July 1981. In their paper, they discussed about an experimental database system called System R, where they demonstrate the usability advantages of the relational data model. It also discussed the lessons learned from the development of System R about the design of relational database systems.
The two major contributions of this paper are the following.
1. The relational database system implementation (System R) where it provides a high-level non-navigational user interface that can support different types of rapidly changing database environments with concurrent users and has the capability to be in a consistent state after a failure.
2. To develop a fully operational database system, researchers followed a three phase program where in the first phase is the development of SQL. A high-level data sublanguage that the System R used to compile database queries into machine level codes.
Based from the experiments done in phase 2 of the System R project, the performance of relational database system is not yet equal to the navigational system where in paths and pointers are used to navigate among data nodes. However, the study hopes for more use of the system in the years ahead since relational database is more likely to be able to adapt to a broad spectrum of unanticipated applications.