1. A computer-implemented mechanism that represents system management information for components of a system as instances of managed object classes, the mechanism comprising a plurality of tables, wherein at least one table includes instance entries for instances of physical object classes representing physical entities, the mechanism being operable: to map attribute entries for attributes of the physical object classes to the instance entries, the allocation of attributes to attribute entries being effected so as to mirror a class inheritance hierarchy; and to map attributes of logical object classes representing logical entities to the tables to represent associations between the physical object classes and the logical object classes.