DATABASE ARRANGED AS A SEMANTIC NETWORK

A semantic network is described in which data is stored in data storage areas at nodes of the network, there being a root node from which all other nodes depend, in a branched structure, and in which data stored at each node includes relationship information about related nodes other than nodes linked by a branch from said node. The relationship information includes a token identifying the type of relationship. The other node in a relationship may be a virtual node, which does not actually exist, but whose data content is stored within the relationship information.