Which of the following will NOT eliminates the ambiguities of a null value?
Define the attribute as required
Define subtypes
Define each attribute as having an initial value that is recognized as blank
Define supertypes
Correct Answer :
D. Define supertypes
Related Questions
Multivalued dependency is removed in
4 NF
3 NF
2 NF
1 NF
Volatile storage
loses its contents when power is switched off.
doesnt loses its contents when power is switched off.
creates backup when power is switched off.
none
In which of the following SET concept is used ?
Network Model
Hierarchical Model
Relational Model
None of these
Data independence means
data is defined separately and not included in programs.
programs are not dependent on the physical attributes of data.
programs are not dependent on the logical attributes of data.
both B) and C).
Noisy channel has ……… .. types of protocols
two
three
four
none
DBMS helps achieve
Data independence
Centralized control of data
Neither A) nor B)
both A) and B)
Datalog is
procedural query language
nonprocedural query language
scan(), write()
none of the above
Referential integrity
controls relationships between operations of an object
controls relationships between instances of a class
controls relationships between attributes in a table
controls relationships between tables in a database
A transaction which completes successfully is called
Granted
Committed
Compensated
Accomplished
A DBMS query language is designed to
support end users who use English-like commands.
support in the development of complex applications software.
specify the structure of a database.
all of the above.
Tape storage is referred to as
sequential access storage
direct access storage
random access storage
none of the above
Object based data models are used in describing the abstraction of the following levels?
Conceptual and view
Only physical
Physical and conceptual
Only conceptual
A relation is said to be in ………. If it doesnt contain partial dependency
1NF
2NF
3NF
BCNF
FDDI protocol operates in
i) Transport layer
ii) Network layer
iii) Datalink layer
iv) Physical layer
i and ii only
ii and iii only
i and iii only
iii and iv only
A relation that has no partial dependencies is in which normal form
First
Second
Third
BCNF
What is the max data capacity of STP?
1 Gbps
56 Mbps
100 Mbps
256 Mbps
A table that displays data redundancies yields ____________ anomalies
Insertion
Deletion
Update
All of the above
A relation which is in 3NF is
in 1NF also
in 2NF also
free from transitive dependencies
All of these
As a side-effect of database update ,the system automatically executes a statement called
a view
a grant permission
a trigger
all of the above
A functional dependency between two or more non-key attributes is called
Transitive dependency
Partial transitive dependency
Functional dependency
Partial functional dependency
Which of the following is a classical approach to database design?
Left Right approach
Right Left approach
Top Down approach
Bottom Up approach
A subschema expresses
the logical view.
the physical view.
the external view.
all of the above.
.................. occurs due to velocity of propagation the frequency varies. Thus various frequency components of a signal arrive at the receiver at different times.
Noise
Delay distortion
Attenuation distortion
Dispersion
In this data model each record can hae more than one parent
Hierarchical model
E-R model
Network based model
none of these
In an Entity-Relationship Diagram Ellipses represents
Attributes
Weak entity set
Relationship sets
Multi-valued attributes
The method of access which uses key transformation is known as
direct.
hash.
random.
sequential.
The control of concurrent execution is left with the
operating system
controller unit of the kernel
concurrency control component of the database system
none
A composite attribute is converted to individual attributes in which of the following normal form ?
first
Second
third
fourth
The number of cursors depend on the
number of queries
number of attributes
size of memory area
none of these
Disk storage is referred to as
sequential access storage
direct access storage
random access storage
none of the above