1. A method for associating a query expression, comprising: adding a metadata table to a database, wherein a portion of the metadata table comprises the query expression; and associating the query expression to a value from a tuple belonging to an existing data table of the database, wherein the existing data table is unmodified, wherein a second portion of the metadata table comprises an element of a tuple that is not listed in the existing data table, wherein the element of the tuple that is not listed in the existing data table comprises an additional query expression, and wherein the metadata table is configured to be queried independently from the existing data table by a user.