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This paper was written way before materialized views obtained their present-day, mainstream acceptance.
This may be the reason why this important work - also covered in a 1982 ACM TODS paper [2] and serving as the basis for a 1991 ACM TODS [3] paper, both by the same author - does not appear to enjoy the visibility it deserves. This fate is shared with pioneering work in incremental view maintenance published in, e.g., the paper "Dynamic Derived Relations Within the RAQUEL II DBMS," by Kathryn C. Kinsley and James R. Driscoll, Proc. 1979 Annual ACM Conference (pp. 69-80) [4]. But that is another digital review.
The present paper pioneers materialized views. Recall that the (logical) plan for computing a relational database query may be expressed as an algebraic query tree with base relations at its leaves and algebra operators at the non-leaf internal nodes. Intermediate nodes correspond to sub-results, and the root corresponds to the result of the query.
The idea, briefly, in the paper is to overlay these query trees for multiple queries, thus creating a graph structure, which is termed a Logical Access Path Schema in the paper. The paper describes how to integrate a query tree into this graph structure. It also describes how to associate probabilities with the graph structure that indicate how frequently its parts are accessed. The resulting structure may then be used during database design for modeling the database access requirements and during operation of the database, as a basis for optimization.
In the related papers, it is shown how to build a pointer structure on top of the base relations, which corresponds to the Logical Access Path Schema. Pointers are to rows in base relations or to other pointers, and a (sub-) result is obtained by materializing the pointers from the base relations and up to the node corresponding to the (sub-) result. This "pointer-materialized" view structure may then be exploited for obtaining better query processing performance.
Copyright © 2000 by the author(s). Review published with permission.