Normalization 

▪UNF to 3 NF 


–UNF to 1 NF 
– remove repeating group along with the PK of the main relation. 



–1NF to 2 NF 
– remove partial dependency (general definition)
partial dependency: exists when there is a functional dependence in which the determinant is only 
part of the primary key [only part of the primary key (B) is needed to determine the value of C] 
【主键的部分决定的依赖关系】



–2NF to 3NF
 – remove transitive dependency. 
transitive dependency exists when there are functional dependencies such that
X Y, YZ, and X is the primary key【两个键都不是主键，但两者存在依赖关系】
▪Dependency diagrams
▪Be careful in choosing the PK!



▪Mapping a set of 3NF relations to a logical model