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US 2002/0059191 A1Published application
Database operation processor
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorTakayuki Tamura
Life of this patent
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Abstract
A database operation processor according to this invention includes a self-join detector for detecting if a self-join operation is included in a query statement for a table in a database and generating a self-join operation expression, a join key classifier for classifying a join key included in a join condition in the operation expression into an equi-join key or a non equi-join key based on the generated self-join operation expression, and a self-join operation executor for sorting records stored in the table by the equi-join key, inputting in the sorted table, executing the generated self-join operation expression, and producing a result for the query statement.
Claims19
A database operation processor comprising:
- a database for storing data;
- a query analyzer for inputting and analyzing a query statement for the database;
- an operation expression generator for generating an operation expression for executing the query statement by inputting an analysis result of the query analyzer;
- and
- an operation expression executor for executing the operation expression generated by the operation expression generator and obtaining data satisfying the query statement from the database,
- wherein the database stores a plurality of tables storing records including at least a column,
- wherein the operation expression generator includes a self-join detector for detecting join processing for joining records stored in two tables according to a determined join condition by inputting an analysis result of the query analyzer, detecting if the detected join processing is a self-join operation processing where said two tables are same and the determined join condition is a join condition for a same column, and generating a self-join operation expression for executing the detected self-join operation processing, and
- wherein the operation expression executor executes the self-join operation expression generated by the self-join detector and producing a result of the self-join operation processing.
5 more elements
A database operation processor comprising:
- a database for storing data;
- a query analyzer for inputting and analyzing a query statement for the database;
- an operation expression generator for generating an operation expression for executing the query statement by inputting an analysis result by the query analyzer;
- and
- an operation expression executor for executing the operation expression generated by the operation expression generator and obtaining data satisfying the query statement from the database,
- wherein the database stores a plurality of tables storing records including at least a column, and
- wherein the operation expression executor includes a self-join detector for detecting a join operation expression for joining records stored in two tables according to a determined join condition by inputting the operation expression generated by the operation expression generator, and detecting if the detected join operation expression is a self-join operation processing where said two tables are same and the determined join condition is a join condition for a same column, and a self-join operation executor for producing a result of the self-join operation processing when the self-join operation processing is detected by the self-join detector.
4 more elements
A database operation processor comprising:
- a database for storing data;
- a query analyzer for inputting and analyzing a query statement for the database;
- an operation expression generator for generating an operation expression for executing the query statement by inputting an analysis result of the query analyzer;
- and
- an operation expression executor for executing the operation expression generated by the operation expression generator and obtaining data satisfying the query statement from the database,
- wherein the database stores a plurality of tables storing records including at least a column,
- wherein the query analyzer includes a self-join detector for inputting the query statement and analyzing a join processing for joining records stored in two tables according to a determined join condition and further detecting if the analyzed join processing is a self-join operation processing where said two tables are same and the determined join condition is a join condition for a same column, and outputting a self-join operation analysis result for instructing the operation expression generator to generate a self-join operation expression for executing the detected self-join operation processing,
- wherein the operation expression generator generates the self-join operation expression according to the self-join operation analysis result output by the self-join detector, and
- wherein the operation expression executor includes a self-join operation executor for executing the generated self-join operation expression by the operation expression generator according to the self-join operation analysis result output by the self-join detector and producing a result of the self-join operation processing.
6 more elements
Dependencies are inferred from the claim text.