The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 06, 1993
Filed:
May. 24, 1989
Gary R Horn, Austin, TX (US);
Timothy R Malkemus, Round Rock, TX (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method and apparatus are disclosed for maintaining the referential integrity of a relational database by determining the validity of each new referential constraint which is brought about by the proposed creation or alteration of a data table within the database. All relationships of a newly created or altered data table are first examined for known non-error conditions in which the new referential constraint will not affect other data tables. Next, self-referencing relationships are examined to detect known error situations. Thereafter, a model is created of a selected portion of the database which includes the newly created or altered data table; all data tables dependent from the newly created or altered data table; all data tables descendant from those dependent tables which are delete-connected to the newly created or altered data table; all data tables which are the parent tables for any data table previously included; and, any ancestor data table having a Cascade delete rule relationship with a parent table previously included. The validity of the new referential constraint is then verified by examining only that portion of the database represented by the model to determine if the proposed relationship allows referential integrity to be maintained.