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ACM Transactions on Database Systems (TODS), Volume 17 Issue 2, June 1992

Constant-time maintainability: a generalization of independence
Ke Wang, Marc H. Graham
Pages: 201-246
DOI: 10.1145/128903.128904
The maintenance problem of a database scheme is the following decision problem: Given a consistent database state &rgr; and a new tuple u over some relation scheme of &rgr;, is the modified state &rgr;...

Rule-based optimization and query processing in an extensible geometric database system
Ludger Becker, Ralf Hartmut Güting
Pages: 247-303
DOI: 10.1145/128903.128905
Gral is an extensible database system, based on the formal concept of a many-sorted relational algebra. Many-sorted algebra is used to define any application's query language, its query execution language, and its optimiztion rules. In this...

Concurrency control for high contention environments
Peter A. Franaszek, John T. Robinson, Alexander Thomasian
Pages: 304-345
DOI: 10.1145/128903.128906
Future transaction processing systems may have substantially higher levels of concurrency due to reasons which include: (1) increasing disparity between processor speeds and data access latencies, (2) large numbers of processors, and (3)...

Optimal weight assignment for signature generation
Chun-Wu Roger Leng, Dik Lun Lee
Pages: 346-373
DOI: 10.1145/128903.128907
Previous work on superimposed coding has been characterized by two aspects. First, it is generally assumed that signatures are generated from logical text blocks of the same size; that is, each block contains the same number of...

On Roth, Korth, and Silberschatz's extended algebra and calculus for nested relational databases
Abdullah U. Tansel, Lucy Garnett
Pages: 374-383
DOI: 10.1145/128903.128908
We discuss the issues encountered in the extended algebra and calculus languages for nested relations defined by Roth, Korth, and Silberschatz.[4]. Their equivalence proof between algebra and calculus fails because of the keying problems and the...