A Correctness Criterion for Schema Dominance Centred on the Notion of 'Information Carrying'

In systems development and integration, whether the instances of a data schema may be recovered from those of another is a question that may be seen profound. This is because if this is the case, one system is dominated and therefore can be replaced by another without losing the capacity of the systems in providing information, which constitutes a correctness criterion for schema dominance. And yet, this problem does not seem to have been well investigated. In this paper we shed some light on it. In the literature, works that are closest to this problem are based upon the notion of 'relevant information capacity', which is concerned with whether one schema may replace another without losing the capacity of the system in storing the same data instances. We observe that the rational of such an approach is over intuitive (even though the techniques involved are sophisticated) and we reveal that it is the phenomenon that one or more instances of a schema can tell us truly what an instance of another schema is that underpins a convincing answer to this question. This is a matter of one thing carrying information about another. Conventional information theoretic approaches are based upon the notion of entropy and the preservation of it. We observe that schema instance recovery requires looking at much more detailed levels of informational relationships than that, namely random events and particulars of random events.