Relational database system
CA 1290856 C · Owner: Wang Laboratories, Inc. · Inventors: Huber, Val J.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Apparatus used in a relational data base system to maintain a dependence between a user-defined field in a row of one base table and the state of a set of rows in another base table. There are three kinds of dependent fields: a count field which contains a count of the rows in the set, a sum field which is the sum of a field in the rows of the set, and a base copy down field which is a, field in the rows of the set which contains a copy of a value in a field in the row of the one base table. The two base tables make up a referenced-referencing pair and the row from the one table has a primary key which is used as a foreign key in the set of rows of the other base table. The apparatus …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted October 15, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended October 15, 2008.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.