Browse Prior Art Database

Data Base Management System

IP.com Disclosure Number: IPCOM000075269D
Original Publication Date: 1971-Aug-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 13K

Publishing Venue

IBM

Related People

Boyle, WW: AUTHOR [+3]

Abstract

This data management system (DMS) provides a method for: (1) keeping history in a data base, (2) separately recording variations within a data base, (3) recording both history and variations in a data base.

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Data Base Management System

1. Introduction.

This data management system (DMS) provides a method for: (1) keeping history in a data base, (2) separately recording variations within a data base, (3) recording both history and variations in a data base.

The DMS requires that each record in the data base have a key field(s). 2. Recording History.

When a data base is created, a master USN field is also created with its value set to 1. Thereafter, the master USN is incremented each time a request is received by the DMS to record a variation in the data base.

Each record in the data base contains an update sequence number (USN) field.

When a new record is stored in the data base, the DMS puts the current value of the master USN field into the USN field of the record. Therefore, when more than one record exists with the same key field(s), the historical sequence of the records is indicated by the values in their USN fields.

Incrementing the master USN field is done when a new generation is created in the data base. The new USN is only put into new records which effectively change one or more old records; the old records are not changed. Thus the number of records are minimized in a history oriented data base, since information required by the new generation that is already in the old data base records is not repeated in the new records. 3. Recording Variations.

Each stored record contains a group identifier (GI) which identifies the group within the data base to which the record belongs.

The DMS can also recognize relationships among different groups of data within a data base. The common information is only stored once and are inherited by all groups. The relationships are described in a dependency graph, which is stored with the control information for the data base. For example, a data base can contain the information for...