Template Join for Processing Recursive Logic Queries in a Loosely Coupled Environment
Original Publication Date: 1988-Jul-01
Included in the Prior Art Database: 2005-Feb-15
A template join technique is presented so as to provide efficient processing of a class of recursive logic queries in a loosely coupled environment. The queries in this class are those represented by one noncyclic tree and one cyclic tree in the extended disjunctive normal form. This technique allows processing all joins in the disk resident database system's workspace, so that joins between an in-memory relation and a database relation are avoided. Only set union operations in main memory are performed on partial results retrieved from the database system. Generally, recursive logic queries can be represented by fixed point formalism. One way of evaluating the queries would be to use Tarski's iterative procedures to obtain the least fixed point.