International Business Machines Corporation

Daniel Virgil Toft

Robert J Bestgen

Lance Christopher Amundsen

Richard Dale Hoffman

Robert Douglas Driesch, Jr

Abdo Esmail Abdo

Query results and statistics regarding them are generated using a novel representation of an n-attribute relation as an order n relational tensor. Orders of the relational tensor respectively correspond to each of the attributes, and each coordinate along an order relates to a key value of the corresponding attribute. Numeric values are stored in the relational tensor, each numeric value representing a count of tuples having the attribute key values that correspond to the coordinate of the numeric value along the orders of the relational tensor. This storage representation is useful in a variety of contexts for enhancing the performance of a RDBMS system. Specifically, a data-representing relational tensor can be used to produce results for join operations such as the SQL operations JOIN, LEFT OUTER JOIN, RIGHT OUTER JOIN and FULL OUTER JOIN.

Generating join queries using tensor representations

Query results and statistics regarding them are generated using a novel representation of an n-attribute relation as an order n relational tensor. Orders of the relational tensor respectively correspond to each of the attributes, and each coordinate along an order relates to a key value of the corresponding attribute. Numeric values are stored in the relational tensor, each numeric value representing a count of tuples having the attribute key values that correspond to the coordinate of the numeric value along the orders of the relational tensor. This storage representation is useful in a variety of contexts for enhancing the performance of a RDBMS system. Specifically, in a first aspect of the invention, a tensor representation can be used to generate statistics for a user query so that the relational database system can determine, from among two candidate approaches, an approach to use in processing the user query based on the statistic. Also, a a data-representing relational tensor can be used to produce results for a restrict operation such as the SQL operations DISTINCT, PROJECTION, EQUALS, LESS THAN, LESS THAN OR EQUAL, GREATER THAN, GREATER THAN OR EQUAL and LIKE.

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Rochester, MN, United States of America

Daniel Virgil Toft