normalization
process of removing redundancy from data
Zeroth Normal Form (0NF)
no rules
“starting point”
redundant data
prime attribute
attribute that is contained in at least on candidate key
dependency closure
non-prime attribute
not in any candidate key (LHS)
First Normal Form (1NF)
only atomic values
Second Normal Form (2NF)
no partial key dependencies
appears in a candidate key
OR is not partially dependent
partial dependency
B is dependent on a part of A
Third Normal Form (3NF)
no transitive key dependency
transitive dependency
X -> Y and Y -> Z, Z -> X does not hold,
Z is transitively dependent on X
Boyce-Codd Normal Form (BCNF)
all determinants are superkeys
Nonadditive Join Test for Binary Decomposition (NJB)
determine if a normalization/decomposition is lossless/nonadditive
shortcut for 3NF and BCNF
if all candidate keys are
atomic
non-overlapping
Transitivity
A determines B and B determines C, so A determines C
Armstrong’s Axioms
Reflexivity
Augmentation
Transitivity
