Patent ID: 7124146

Claim:
A method performed on a computer system for estimating a cardinality value for a set of data values, the method comprising: (a) initializing a data structure for representing counts; (b) obtaining a data value from said set of data values; (c) transforming said data value into a transformed string; (d) modifying said data structure with said transformed string; (e) obtaining a summary statistic value from said modified data structure; and (f) generating said estimated cardinality value using said summary statistic value, wherein generating said estimated cardinality value step (f) is performed for each distinct occurrence of a hashing function within a plurality of hashing functions, further comprising: (f1) generating a cardinality estimate value associated with each instance of said hashing function; (f2) summing said cardinality estimate values; (f3) averaging said cardinality estimate values to produce a raw cardinality estimate value, and; (f4) adjusting said raw cardinality estimate value for data value collisions to produce a final cardinality estimate value.