Best Table Design breaks down the table's database into a smaller Table until each TABLE is DEPEEND ON TABLE whose KEY why? Reduce repetition (Redundancy)? * Refers to the storage of information *? Clear inconsistent (Consistency)? * Refers to the data of the information *?
Design 3 style:
(1) Frist Normal Form (1NF)
"There is only one value for each data bar." Check that there is an attribute having a duplicate value, it is moved to a new entity.
(2) Second Normal Form (2NF)
"All the data columns of the Primary Key and Primary Key have full functional dependency." Delete is not dependent on the data items of the entire key, and other properties correspond to the primary key.
(3) THIRD NORMAL FORM (3NF)
"All the data bars that are not Primary Key do not have Full Functional Dependency." Delete dependencies without completely relying on primary key, and non-primary keys cannot have one correspondence.
