Fact structure and its application to updates in relational databases

摘要

We introduce the fact structure of a relation: a user defined semantic structure describing the information (called facts) represented by a tuple. We argue that regarding tuples as units of information leads to many problems in the relational model, rather, we propose facts as units of information, with tuples used to represent facts. These ideas are further refined by introducing primary facts, namely, those facts that are considered more important by a user. Then we study the problem of updates in such a fact-oriented environment, and characterize “deletable” and “nondeletable” facts, and prove that it is possible to delete deletable facts with no side effect.