what is Normalization means..?
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Answer Posted / firoz basha
Normalization is a series of steps followed to obtain a
database design that allows for consistent storage and
efficient acess of data in a relational database.
These steps reduce data redundancy and risk of data
becoming inconsistent.
there are 5 types of normal forms(NF) :
1 NF , 2NF, 3NF, 4NF, 5NF
1NF:- A relation is said to be in first normal form , if it
dows not contain any repeating groups or elements (or) if
all the values are atomic
2 NF:- A relation is said to be in Second Normal form, if
and only if it is in 1 NF and all the non-key attributes
are fully functionally dependent on the primary key.
3 NF:- A relation is said to be in 3rd normal form, if and
only if it is in 2NF and every non-key attribute is
non-transitively dependent on the primary key.
(or) every attribute is independent of all the other non-
key attributes.
BCNF:- A relation is said to be in BCNF, if every attribute
on which some other attribute is also a candidate for
primary key of a relation.
4 NF:- A relation is said to be in 4th normal form, if and
only if it is in 3NF and it should not contain any
multivalued dependencies.
5 NF :-A relation is said to be in 5 NF , if and only it it
is in 4 NF and every join dependency in R is implied by the
candidate key.
Any clarifications and for examples,
mail me : firozbashashaik@yahoo.com
| Is This Answer Correct ? | 44 Yes | 4 No |
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