Interested to Buy Any Domain ? << Click Here >> for more details...
Normalization in DB2 – first normal form, second normal form
- 4 Answers
- 22189 Views
- Virtusa, I also Faced
- E-Mail Answers
Answers were Sorted based on User's Feedback
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.
| Is This Answer Correct ? | 7 Yes | 1 No |
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.
| Is This Answer Correct ? | 7 Yes | 3 No |
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 |
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 |
How will you delete duplicate records from a table?
Is it possible to update a primary key value? If not, what is the error code given? If yes, can more than 1 primary key column be updated at a time?
max number of columns in a db2 table?
What do you need to do before you do EXPLAIN ?
What is a SELECT statement?
What do you mean by cursor?
Can DASD types assigned to storage groups be intermixed (i.e., 3350s and 3380s)?
What is an asychronous write?
we can code COPY DCLGEN or INCLUDE DCLGEN, At which stage of the precompilation , dclgen get expanded if we write 1) copy 2) include one question about dclgen.. Is it mandatory to use declare table in dclgen.. I think no...but it will be used by the precompiler to validate the table name,column name etc.., can one clear my doubt ..is it necessary to include declare table or not?
What is copy pending and check pending in db2?
Explain in detail about buffer manager and its functionalities?
How to resolve -407 sql code in DB2?
COBOL 
