CP363 Lecture Notes - Lecture 19: Multivalued Dependency, Candidate Key, Superkey
8 Apr 2019
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Definition: x->y holds whenever two tuples have the same value for x they must have the same value for y. We can conclude that certain fd do not exist because there are tuples that show a violation of those dependencies. If they have the same value for x attribute then they must have the same value for y attributes. Normalization: start with a table and break it up so that the pieces satisfy a normal form. Normal form: condition using keys and fds of a relation to certify whether a relation schema is in a particular normal form. Based on keys and fds of a relation schema. Normalization is carried out in practice so that the resulting designs are of high quality and meet desirable standard. A super key is a set of attributes that determined uniquely the values of every other tuple in the table. A key is a superkey plus minimal number of attributes.
