Defining the notion of 'Information Content' and reasoning about it in a database

The problem of 'information content' of an information system appears elusive. In the field of databases, the information content of a database has been taken as the instance of a database. We argue that this view misses two fundamental points. One is a convincing conception of the phenomenon concerning information in databases, especially a properly defined notion of 'information content'. The other is a framework for reasoning about information content. In this paper, we suggest a modification of the well known definition of 'information content' given by Dretske(Knowledge and the flow of information,1981). We then define what we call the 'information content inclusion' relation (IIR for short) between two random events. We present a set of inference rules for reasoning about information content, which we call the IIR Rules. Then we explore how these ideas and the rules may be used in a database setting to look at databases and to derive otherwise hidden information by deriving new relations from a given set of IIR. A prototype is presented, which shows how the idea of IIR-Reasoning might be exploited in a database setting including the relationship between real world events and database values.