1. A method of searching a database comprising: providing a plurality of relational models, each one of the plurality of relational models includes one relational model of one subset of a database; inputting a first query; creating a relational model of the first query, wherein the relational model of the query includes a plurality of relations, each one of the plurality of relations has a first query term pair and a first query plurality of types of relational summation metrics (RSMs); comparing the relational model of the first query to each one of the plurality of relational models of the subsets; and outputting a first plurality of identifiers of the subsets relevant to the first query.