Title :
Natural joins in relational databases with indefinite and maybe information
Author_Institution :
Dept. of Comput. Sci., Illinois Inst. of Technol., Chicago, IL
Abstract :
Natural joins are defined, in a semantically correct way, on data structures, called I-tables, of an extended relational database model with indefinite and maybe information. An algorithm for computing natural joins under the extended model is proposed which reduces the number of pair-up operations and block accesses to a linear order of complexity with respect to the size of I-tables. Procedures for the extended natural joins are examined with respect to efficiency, which is evaluated based upon the number of pair-up operations and I/O block accesses. A linear order of pair-up operations is achieved by using the `compare, concatenate, and then permute´ strategy, and a linear order of I/O activities is attained by employing virtual relations with pointers
Keywords :
data structures; relational databases; I-tables; compare; concatenate; data structures; indefinite; maybe information; natural joins; pair-up operations; permute; pointers; relational databases; virtual relations; Computer science; Data structures; Mathematical model; Relational databases;
Conference_Titel :
Data Engineering, 1991. Proceedings. Seventh International Conference on
Conference_Location :
Kobe
Print_ISBN :
0-8186-2138-9
DOI :
10.1109/ICDE.1991.131460