A computer system that includes a storage medium. The storage medium stores a database. The database includes tables. Each table includes g at least one column and at least one row. The tables describe components of a hierarchy in which hierarchical relationships between components of the hierarchy are defined. The tables include a component table and component-specific tables. The component table is a self-referential table that describes the hierarchy. Each row of the component table is specific to a unique component. The components of the hierarchy encompass component types. Each column of component table is configured to be edited by a user through use of a worksheet. Each component-specific table encompasses only components of the hierarchy such that each component has a component type that is a specific component type.