Patent ID: 8880505

Claim:
A method for evaluating a conjunctive query, the method executed as a computer program by a general purpose computer, the conjunctive query comprising an at least one first predicate having variables; wherein the at least one first predicate is a relational predicate that is evaluated with a first engine using a relational database, and an at least one second predicate having variables, wherein the at least one second predicate is an external predicate that is evaluated using a second engine without using a relational database; the method comprising the steps of: defining the relational predicates as untreated and defining the external predicates as untreated; receiving a first algorithm (A) that defines a method of dividing up the external predicates; extracting external predicates based on the received first algorithm (A) and marking them as treated; associating the extracted external predicates with untreated relational predicates that appear as variables of the external predicates and indicating the associated relational predicates as treated; evaluating the extracted external predicates using a second algorithm to produce a result; repeating said extracting, associating and evaluating for additional sets from the external predicates and performing a join operation on the results.