ProductMap adds to Symbol

The values in the three primary source tables are treated as base case values, and the ProductMap table allows us to multiply them into new Symbol tuples as desired. Note from the create table statements in syms.sql that Underlying and Symbol have nearly the same structure, being in essence type-exchange-name triples. Each product mapping gives directions for creating a new, derived symbol triple from an underlying, and incidently stands for the derivative relationship between the two, since that is not directly visible except by matching on the long name comment attributes, a tedious and fragile business at best.

Bill Pippin 2010-01-14