Abstract: A database management system returns data from a database table in response to a database query. It does so by accessing an ordered list that indicates an order of retrieval for one or more rows in the database table and returning data from a row that is first in the order of retrieval before returning data from other rows. In some embodiments, after successfully returning the data, the row is deleted.

Abstract: A method, apparatus, and article of manufacture for optimizing a star join operation in relational database management systems (RDBMS). A cross-product is generated from a plurality of dimension tables referenced by the star join. The join columns of the cross-product are then hashed to create a hash-row value. Using the hash-row value, a Star Map is probed to determine whether a record exists in a fact table that corresponds to the cross-product, wherein a first portion of the hash-row value is used to select a row of the Star Map and a second portion of the hash-row value is used to select a column of the selected row of the Star Map. The fact table is accessed to perform a merge join with the cross-product when the selected column of the selected row of the Star Map indicates that the record exists in the fact table.