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US 8,818,987 B2Granted
Converting union commands to union all commands
AssigneeInternational Business Machines Corporation
InventorsEric L. Barsness, John M. Santosuosso
Life of this patent
Estimating the term…
Abstract
In one aspect, a method is provided. The method includes: (1) identifying in a query of a database a union command involving data in the database that is mutually exclusive; and (2) changing the union command to a union all command.
Claims18
A method, comprising:
- identifying, in a query of a database, a union command involving data that includes a first data set and a second data set wherein the first data set and the second data set are mutually exclusive;
- and
- improving performance of the query by changing the union command to a union all command,
- wherein identifying a union command includes determining whether a definition of the data in the first data set excludes data in the second data set and determining whether the data includes a constraint for a predicate where the data is exclusive.
1 more element
A device, comprising:
- a server including a database;
- and
- logic configured to:
- identify, in a query of the database, a union command involving data that includes a first data set and a second data set wherein the first data set and the second data set are mutually exclusive;
- and
- improve performance of the query by changing the union command to a union all command,
- wherein the logic configured to identify a union command includes logic to determine whether a definition of the data in the first data set excludes data in the second data set and logic to determine whether the data includes a constraint for a predicate where the data is exclusive.
4 more elements
A database system, comprising:
- a server, including:
- a database;
- and
- historical data related to the database;
- and
- logic configured to:
- identify, in a query of the database, a union command involving data that includes a first data set and a second data set wherein the first data set and the second data set are mutually exclusive;
- and
- improve performance of the query by changing the union command to a union all command,
- wherein the logic configured to identify a union command includes logic to determine whether a definition of the data in the first data set excludes data in the second data set and logic to determine whether the data includes a constraint for a predicate where the data is exclusive.
7 more elements
Dependencies are inferred from the claim text.