1. If a relational database table is in the third normal form, it is also in a.

Question

1. If a relational database table is in the third normal form, it is also in

a.   the first normal form.

b.   the second normal form.

c.   the Boyce-Codd normal form.

d. both a. and b.

2. ______________________ guarantee(s) the access structure is always balanced when a lot of updates such as insertions and deletions of file records occur.

a.   Multi-Way search tree

b.   Dynamic hashing

c. B-tree/B+-tree

d.   Multilevel index   

3. Please indicate what the highest normal form is for the given relation schema R(A, B, C, D), the key for the schema: AB, and the set of functional dependencies, AB -> C, AB -> D.

a. The first normal form (1NF)

b. The second normal form (2NF)

c. The third normal form (3NF)

d.   The Boyce-Codd normal form (BCNF)

4. If there is a one-to-many relationship between entity A and B, then

a. there exists a functional dependency from the primary key in A to the primary key in B, i.e.,
PK(A) ? PK(B).

b.   there exists a functional dependency from the primary key in B to the primary key in A, i.e.,
PK(B) ? PK(A).

c.   both a. and b.

d. neither a. nor b.

5. A database language consists of

a.   data definition language

b.   data manipulation language

c.   both a. and b.

d.   neither a. nor b.

Explanation / Answer

1.answer: d

Explanation:

first normal form: attribute values are atomic and nested relations not allowed,multivalued attributes not allow

Second normal form:non key attribute is fully depend on key attribute.

if there is any partial dependencies exist remove it.

Third normal from :if there is any transitive dependecies are exists remove it.

BCNF more strict than 3NF.

a relation is in BCNF it already in 1NF,2NF,3NF.

a relation is in 3NF it is in 1NF ,2NF, but not in BCNF.

2.answer: c

B/B+ Trees are dynamic indexing techniques they balance the tree and provide guarantte to access very fastly.

and keeping all the nodes at same distance.

3.answer: b

given ralation is in 2NF nonkey fully depend on key attribute.(C& D are non keys depend on key AB)

It not in 3NF because C is not part of key or D is not part of key hence the Relation is in 2NF

in 3NF FD: X->Y If either x is primary key or Y is part of key.

4.answer: c

5.answer:C

Explanation:

data definition language: to specify the various data base schemas and their attributes and their domains. by using the following commands. create ,alter ,drop, truncate the tables

data manipulation language:to perform various data manipulations like

retrival of data stored in database,inserting information into database, deletion of information from the database and modification of data.

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