Abstract

In this paper a file organization scheme designed to replace the use of the popular secondary index filing scheme (or inverted files on secondary key fields) is described. Through the use of redundancy and storing keys (or access numbers of the records) that satisfy different combinations of secondary index values in “buckets,” it is possible to retrieve all keys satisfying any input query derived from a subset of fields by a single access to an index file, although each bucket may be used for many combinations of values and a combination of buckets may be required for a given query. The method which, in its degenerate case, becomes the conventional secondary index filing scheme works similarly but has the following advantages: (1) the elimination of multiple accesses in many cases; (2) the elimination of false drops; (3) the elimination of computer time to perform intersection of key sets each qualified for one secondary index field only; and (4) the avoidance of long strings of keys when an index field appearing in a query has very few possible values. Redundancy, in some cases, is the same as the secondary indexing method. In the general case, trade-off between the number of accesses for query and redundancy exists.

Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.