The subject invention leverages data sampling techniques to provide an efficient means to determine co-occurrence count estimations for objects and features from relational data, simplifying measure-of-association determinations. By providing an efficient mechanism to estimate co-occurrence counts, instances of the subject invention can be incorporated directly into a database, increasing its versatility and performance for such uses as collaborative filtering recommendations. Other instances of the subject invention can be utilized for enhancing database query selectivity, optimizing query performance through employment of a priori co-occurrence counts.