1. A method for estimating a selectivity of a query containing at least one column-associated condition related to column attributes of a relational database table, the method comprising: (a) generating a dataset by sampling a plurality of queries applied against the database, wherein the dataset includes a plurality of query conditions and information related to combinations of said query conditions, (b) determining at least one regression function that reflects correlations between particular query conditions based on said dataset, (c) determining a table-specific estimate of a cardinality of a query based upon the regression function serving as a data mining model.