International Business Machines Corporation

Roy Froehlich

Charles Matula

Thomas A Jobson, Jr

Edith A Kanyock

Arnold M Rosenberg

Howard S Bloom

Dallas L Johnson

A method and system for rewriting Structured Query Language (SQL) statements. A SQL statement having search criteria including conditions pertaining to fields in database tables is received. A table from the SQL statement listing all combinations of the search criteria is created, every combination reflecting a subset of information used to determine combined results. A set of patterns among the possible combinations of the SQL statement based on the fields referenced in the combinations is identified. The table based on the set of patterns is sorted. Based on the sorting, the table is divided into temporary tables which are joined with the SQL statement. New temporary tables are generated. Each new temporary table includes results of a search conducted using a separate portion of the SQL statement as joined with the set of temporary tables. All results from the new temporary tables are combined into a single result table.

Method, system and program product for rewriting structured query language (SQL) statements

Under the present invention, a SQL statement having search criteria is received. Upon receipt, a table that lists all possible combinations of the search criteria is created. From the table, a set of patterns among the possible combinations is identified. Based on these patterns, the table is then sorted. Once sorted, the table is divided into a set of temporary tables based on the set of patterns/sorting operation. The set of temporary tables are then individually joined with the SQL statement and separate searches are conducted. A new set of temporary tables is then generated and populated with results of the separate searches. These result tables are then unioned/combined into a single result table.

Under the present invention, when a SQL statement having a full select portion that references a view containing a join operation (e.g., a LOJ operation) is received, the reference to the view will be moved out of the full select portion. Once moved, the view and its join operation will be resolved separately from the SQL statement. The results of this resolution will be placed in a temporary table. A reference to the temporary table is then inserted in the full select portion, and the SQL statement is thereafter performed.

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Roy Froehlich