Implementation of a Structured English Query Language The relational model of data, the XRM Relational Memory System, and the SEQUEL language have been covered in previous papers and are reviewed. SEQUEL is a relational data sublanguages intended for the ad hoc interactive problem solving by non-computer specialists. A version of SEQUEL that has been implemented in a prototype interpreter is described. The interpreter is designed to minimize the data accessing operations required to respond to an arbitrary query. The optimization algorithms designed for this purpose are described. CACM October, 1975 Astrahan, M. M. Chamberlin,D. D. relational model, query language, nonprocedural language, database, data structure, data organization 3.74 3.75 4.22 4.33 4.34 CA751004 JB January 6, 1978 11:02 AM 2155 4 2715 2406 4 2715 2710 4 2715 2715 4 2715 2716 4 2715 2717 4 2715 2718 4 2715 2765 4 2715 2817 4 2715 2888 4 2715 2901 4 2715 2957 4 2715 2959 4 2715 2965 4 2715 3087 4 2715 3154 4 2715 2046 5 2715 2710 5 2715 2715 5 2715 2715 5 2715 2715 5 2715 2716 5 2715 2901 5 2715 1515 6 2715 1976 6 2715 2046 6 2715 2046 6 2715 2046 6 2715 2715 6 2715 2715 6 2715 2715 6 2715 616 6 2715