John P Rust

US Patent:

6728709, Apr 27, 2004

Filed:

Jun 22, 2001

Appl. No.:

09/887640

Inventors:

James M. Plasek - Shoreview MN
John C. Rust - Brooklyn Park MN
Don W. Frauendienst - Coon Rapids MN

Assignee:

Unisys Corporation - Blue Bell PA

International Classification:

G06F 1730

US Classification:

707 8, 707101, 711152

Abstract:

A method and apparatus for locking a database table having a plurality of partitions. In various embodiments, lock status codes are maintained for both a database table and for the partitions of the database table. The partition locks do not need to be updated when a lock is granted for the database table since a separate table lock status code is maintained. The separate table lock status code improves database application performance and simplifies programming of explicit lock operations.

US Patent:

6768985, Jul 27, 2004

Filed:

Aug 30, 1999

Appl. No.:

09/385771

Inventors:

James M. Plasek - Shoreview MN
John C. Rust - Brooklyn Park MN

Assignee:

Unisys Corporation - Blue Bell PA

International Classification:

G06K 1730

US Classification:

707 2, 707100, 711163, 711173

Abstract:

A method and apparatus for managing a database having a plurality of partitions are provided in various embodiments. The database is managed by users of a first user class and accessible to users of a second user class. Respective partition states are established for the partitions of the database, and access is provided to users of the first user class to partitions having a first partition state. Users of the second user class are denied access to partitons having the first partition state, and users of the second user class are provided access to partitions having a second partition state.

US Patent:

7356549, Apr 8, 2008

Filed:

Apr 11, 2005

Appl. No.:

11/102990

Inventors:

Kelsey L. Bruso - Minneapolis MN, US
James M. Plasek - Shoreview MN, US
John C. Rust - Brooklyn Park MN, US

Assignee:

Unisys Corporation - Blue Bell PA

International Classification:

G06F 17/30

US Classification:

707200

Abstract:

A system and method for managing multiple partitions of a database are disclosed. According to one embodiment, each partition contains a subset of all records of the database, and is respectively associated with a secondary index B-tree, and a primary key B-tree. To retrieve a data record from the database, a partition is selected and a search is initiated on the associated secondary index B-tree for one or more records having a desired secondary index value. If records are so located, a primary key value obtained from one of the records is used to search the associated primary key B-tree to locate the data. In some cases, the search of the secondary index B-tree may not find the desired secondary index value within the selected partition. In these instances, pointers directed to one or more other partitions are used to locate records containing the desired secondary index value.