Normalization is a standard to model tables and relationships in a manner to avoid redundancy and other undesirable dependencies or effects on the data.
There are six different normal forms, which are given as follows:
i. First Normal Form (INF) — A relation R is in INF if and only if all the underlying domains contain atomic values only.
ii. Second Normal Form (2NF)— k relation R is in 2NF if and only if it is in INF and every non-key attribute is fully functionally dependent on the primary key.
It means that all the columns except the primary key column should depend on the primary key column for a
table to be in 2NF.
iii. Third Normal Form (3NF) — A relation R is in 3NF if and only if it is in 2NF and every non-key attribute is non-transitively dependent on the primary key.
It means that all the columns except the primary key column should be directly dependent on the primary key
column and not through any other column.
? Boyce Codd Normal Form (BCNF) — A relation R is in BCNF if and only if every determinant is a candidate key.
In any table, there exists a primary key, which is used to determine rest of the column values. If there is more than one such set of columns that can determine rest of the column values, then this set of columns is called a candidate key or an alternate key.
iv. Fourth Normal Form (4NF)— k relation R is in 4NF if and only if there exists multi-valued dependency in R, say A->> B, then, all the attributes of R are also functionally dependent on A.
v. Fifth Normal Form (5NF) — A relation R is in 5NF or Project-Join Norma Form (PJNF) if and only if every join dependency is impl ed by candidate keys.
There are six different normal forms, which are given as follows:
i. First Normal Form (INF) — A relation R is in INF if and only if all the underlying domains contain atomic values only.
ii. Second Normal Form (2NF)— k relation R is in 2NF if and only if it is in INF and every non-key attribute is fully functionally dependent on the primary key.
It means that all the columns except the primary key column should depend on the primary key column for a
table to be in 2NF.
iii. Third Normal Form (3NF) — A relation R is in 3NF if and only if it is in 2NF and every non-key attribute is non-transitively dependent on the primary key.
It means that all the columns except the primary key column should be directly dependent on the primary key
column and not through any other column.
? Boyce Codd Normal Form (BCNF) — A relation R is in BCNF if and only if every determinant is a candidate key.
In any table, there exists a primary key, which is used to determine rest of the column values. If there is more than one such set of columns that can determine rest of the column values, then this set of columns is called a candidate key or an alternate key.
iv. Fourth Normal Form (4NF)— k relation R is in 4NF if and only if there exists multi-valued dependency in R, say A->> B, then, all the attributes of R are also functionally dependent on A.
v. Fifth Normal Form (5NF) — A relation R is in 5NF or Project-Join Norma Form (PJNF) if and only if every join dependency is impl ed by candidate keys.