1. A method for combining data within a database system, the method comprising: performing a first merge operation to merge source data from a source data structure with a first destination data structure, wherein the source data structure and the destination data structure are relational data structures; and initiating a second merge operation to merge a set of data that is returned by the first merge operation as a portion of the source data with a second destination data structure, wherein the second merge operation is initiated independent of any other portion of the source data undergoing the first merge operation.