Normalization in DB2 – first normal form, second normal form

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Normalization in DB2 – first normal form, second normal form ..

Answer / mohan.s

Second normal form (2NF) If a table has a composite key,
all attributes must be related to the whole key:

• The database must meet all the requirements of the
first normal form.

• The relational schema should not have any partial
functional dependency i.e. No proper subset of the primary
key should derive a functional dependency belonging to the
same schema. For example, consider functional dependencies
FD:{AB->C, A->D, C->D} here AB is the primary key, as A->D
this relational schema is not in 2NF.

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7 Yes

1 No

Normalization in DB2 – first normal form, second normal form ..

Answer / mohan.s

First normal form (1NF) lays the groundwork for an
organised database design:

• Ensure that each table has a primary key: minimal
set of attributes which can uniquely identify a record.

• Eliminate repeating groups (categories of data
which would seem to be required a different number of times
on different records) by defining keyed and non-keyed
attributes appropriately.

• Atomicity: Each attribute must contain a single
value, not a set of values.

• 'First normal form' depends on functional
dependency formula f(x)=y. For every value of x there is
value for y.

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7 Yes

3 No

Normalization in DB2 – first normal form, second normal form ..

Answer / mohan.s

The formal classifications describing the level of database
normalization in a data model are called Normal Forms (NF)
and the process of doing this is Normalization.

Is This Answer Correct ?

8 Yes

6 No

Normalization in DB2 – first normal form, second normal form ..

Answer / mohan.s

Third normal form (3NF) requires that data stored in a
table be dependent only on the primary key, and not on any
other field in the table.

• The database must meet all the requirements of the
first and second normal form.

• All fields must be directly dependent on the
primary key field. Any field which is dependent on a non-
key field which is in turn dependent on the Primary Key (ie
a transitive dependency) is moved out to a separate
database table.

Is This Answer Correct ?

4 Yes

3 No

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