15. The computer-readable storage medium of claim 10 , wherein the first value of the skyline probability attribute of the first joined tuple includes a product of the value of the second existence probability attribute of the tuple selected from the second set of tuples and the value of the first existence probability attribute of the tuple selected from the first set of tuples.
15. The computer-readable storage medium of claim 10 , wherein the first value of the skyline probability attribute of the first joined tuple includes a product of the value of the second existence probability attribute of the tuple selected from the second set of tuples and the value of the first existence probability attribute of the tuple selected from the first set of tuples. 17. The computer-readable storage medium of claim 15 , wherein the operations further comprise: identify a dominance relationship among the first tuple and other tuples in the second relation based on a first local attribute of the second relation.