1. A method for running a query on a database table, said table comprising a column of values and including for each of a plurality of substrings, a corresponding index over the column, wherein each corresponding index includes a respective entry for each value in the column, the respective entry for a particular value being indicative of whether the corresponding substring occurs in that particular value, the method comprising the steps of: identifying a set of values that potentially satisfy the query based on the plurality of corresponding indices.