Patent ID: 8176088

Claim:
A computer system for estimating a cardinality value for a set of data values comprising: means for providing an initial estimated cardinality value for the set of data values; means for initializing a data structure for representing an array of counts; means for obtaining a data value from said set of data values, the data value being added to or deleted from the set of data values; means for transforming said data value into a transformed string; means for modifying said data structure and the array of counts with said transformed string; means for determining whether a new cardinality value should be estimated for the set of data values based on the modified array of counts; means for obtaining a summary statistic value from said modified data structure in response to determining that the new cardinality value should be estimated, wherein the summary statistic value is based on the array of counts; and means for generating said new estimated cardinality value using said summary statistic value.