Abstract: Disclosed is a method, system, and program for performing a join operation on a multi-column table and at least two satellite tables having a join condition. Each satellite table is comprised of multiple rows and at least one join column. The multi-column table is comprised of multiple rows and at least one column corresponding to the join column in each satellite table. A join operation is performed on the rows of the satellite tables to generate concatenated rows of the satellite tables. One of the concatenated rows is joined to the multi-column table and a returned entry from the multi-column table is received. A determination is then made as to whether the returned entry matches the search criteria. If so, a determination is made as to whether one of the satellite tables has duplicates of values in the join column of the returned matching entry or the multi-column table has duplicate entries in the join columns.

Abstract: A method, apparatus, and article of manufacture for a computer implemented query compiler. A query is executed in a computer, the query being performed by the computer to retrieve data from a database stored on a data storage device connected to the computer. The query is received containing at least one variable. At execution time, a value is determined for each variable in the query. A filter factor is estimated using the determined value for each variable. Then, an access path is determined for the query using the estimated filter factor.

Abstract: A method, apparatus, and article of manufacture for a computer implemented query compiler. A query is executed in a computer, the query being performed by the computer to retrieve data from a database stored on a data storage device connected to the computer. The query is received containing at least one variable. At execution time, a value is determined for each variable in the query. A filter factor is estimated using the determined value for each variable. Then, an access path is determined for the query using the estimated filter factor.

Abstract: A method and apparatus for generating static, dynamic and hybrid sparse indices for use with workfiles used by SQL queries in a relational database management system.

Abstract: A method, apparatus and article for manufacture for generating static, dynamic and hybrid sparse indices for use with workfiles used by SQL queries in a relational database management system. A workfile and a sparse index structure are temporarily created in the computer during execution of the query by the computer. The workfile stores intermediate relations resulting from execution of a portion of the SQL query, wherein the intermediate relations comprise sorted rows for an inner table referenced in the SQL query. The sparse index structure contains one or more entries indicating at least an approximate location for at least some of the rows in the workfile. As one or more rows from an outer table referenced in the SQL query are retrieved, the entries of the sparse index structure are searched for a closest matching entry for each retrieved row. The sorted workfile is then scanned for a row matching each retrieved row using the closest matching entry from the sparse index structure as a starting position.