1. A product data-model stored in a memory associated with a computer, said product data-model representing product information about at least one component that is a constituent of at least one parent assembly, comprising: a parent assembly holding information for associating the component with the parent assembly; a plurality of component-usages for holding information relating to usages of the component, said component-usages being operatively connected to the parent assembly; a plurality of logical component-usages for holding information relating to logical usages of the component, said component-usages being operatively connected to said component-usages; and said parent assembly, said component-usages and said logical component-usages being hierarchically interconnected.