Chi A Hoang

US Patent:

6374236, Apr 16, 2002

Filed:

Dec 4, 1999

Appl. No.:

09/454729

Inventors:

James Chen - Torrance CA
Chi Kim Hoang - Palo Alto CA
Mark Anthony Hodgens - San Diego CA
Frederick Stuart Kaufmann - Irvine CA
Rolf Günter Erich Stegelmann - Valencia CA

Assignee:

NCR Corporation - Dayton OH

International Classification:

G06F 1730

US Classification:

707 2, 707 10

Abstract:

A method, apparatus, and article of manufacture for accessing a subject table in a computer system. The subject table is partitioned across a plurality of processing units of the computer system. A trigger is defined for the subject table, such that when a triggering event occurs on the subject table, a triggered action is performed. Both the triggering event and triggered action can be performed in parallel by the computer system. A spool table is generated for each partition of the subject table, wherein the spool table stores one or more necessary records accessed from the subject table by the triggering event. In this manner, triggered actions that refer to these necessary rows need not access the subject table again.

US Patent:

6470331, Oct 22, 2002

Filed:

Dec 4, 1999

Appl. No.:

09/454730

Inventors:

James Chen - Torrance CA
Chi Kim Hoang - Palo Alto CA
Mark A. Hodgens - San Diego CA
Fred S. Kaufmann - Irvine CA
Rolf G. E. Stegelmann - Valencia CA

Assignee:

NCR Corporation - Dayton OH

International Classification:

G06F 1730

US Classification:

707 2, 707 10

Abstract:

A method, apparatus, and article of manufacture for accessing a subject table in a computer system. The subject table is partitioned across a plurality of processing units of the computer system. A user query or other request to access the subject table is split into a plurality of step messages, wherein each of the step messages is assigned to one of the processing units managing one or more of the partitions of the subject table. A plurality of actions are identified for each of the step messages, and one or more necessary records for these actions are retrieved from the partition of the subject table and stored into a corresponding partition of a spool table. The necessary records are selected in such a manner that none of the actions involved in the request need to access the partition of the subject table. The actions from the step message are then performed against the partitions of the spool table rather than the partitions of the subject table. An optimizer function uses information from the spool table to generate more efficient execution plans for the step message and its associated actions.

US Patent:

57616574, Jun 2, 1998

Filed:

Dec 21, 1995

Appl. No.:

8/577681

Inventors:

Chi Kim Hoang - Inglewood CA

Assignee:

NCR Corporation - Dayton OH

International Classification:

G06F 700

US Classification:

707 4

Abstract:

A method of optimizing a query and its subqueries together in a global manner regardless of the nesting levels. All joins in different nesting levels are effectively converted into joins in the same level by assigning a nesting level attribute to relations, assigning properties to the predicate, and assigning nesting level attributes and minimum relation set attributes to join predicate operands. The joins and their predicates are then considered as if they were contained in only the main query according to a set of rules based on the attributes of the relations and the join predicates.