1 research outputs found
Is 2NF a Stable Normal Form?
Traditionally, it was accepted that a relational database can be normalized
step-by-step, from a set of un-normalized tables to tables in , then to
, then to , then (possibly) to . The rule applied to a table in
in order to transform it to a set of tables in seems to be too
straightforward to pose any difficulty.
However, we show that, depending on the set of functional dependencies, it is
impossible to reach and stop there; one must, in these cases, perform the
normalization from to as an indecomposable move. The minimal setup
to exhibit the phenomena requires a single composite key, and two partially
overlapping chains of transitive dependencies.Comment: 10 pages, 1 figur