Which of the following is/are error-free channel(s)
i) Noisy channel
ii) Noiseless channel
i only
ii only
Both
None of these
Correct Answer :
B. ii only
Related Questions
Relational Algebra is
Data Definition Language.
Data Manipulation Language
Procedural query Language
None of the above
The privilege lists include
i) select
ii) insert
iii) update
iv) delete
only i)
only i) ii)
only i) ii) iii)
i) ii) iii) iv)
Noiseless channel has ……… types of protocols.
2
3
4
5
By default a user who has been granted some form of authorization
is allowed to pass them to others
is not allowed to pass them to others
may be or may not be allowed to pass them to others
none
Functional dependencies are generalization of
Relation dependencies
Data dependencies
key dependencies
none of the above
The maximum number of children in a B-tree of order m is
m+1
m
m-1
m/2
Which of the following aggregate function doesnt ignore NULLs in its results?
COUNT
COUNT(*)
MAX
none of these
Commit operation …………… writes the changes made to the database.
temporarily
permanently
none of these
all of the above
In E-R Diagram weak entity set are represented by
Ellipse
Dashed ellipse
Dashed Rectangle
Doubled Rectangle
A fragmentation is categorized in
1 part
2 part
3 part
4 part
The ability to modify the conceptual schema without causing any change to the application program is known as
Physical data independence
Logical data independence
External data independence
Static data
Which one of the following is provided by a data dictionary ?
User data
Database structure data
Sorted data
Functional data
DBMS helps achieve
Data independence
Centralized control of data
Neither A) nor B)
both A) and B)
The syntax to select all column from the table is
select all from tablename
select * from tablename
select from tablename
none of these
In an E-R diagram attributes are represented by
rectangle.
square.
ellipse.
triangle.
A transaction is said to have terminated if it has
either committed or aborted
either partially committed or aborted
either committed or failed
none of these
If the .................... is too much, the receiver may not be able to detect the signal at all or the signal may fall below the noise level.
Noise
Delay
Dispersion
Attenuation
When all attributes in a relation tuple are not functionally dependent only on the key attribute. Which of the following normalization is needed?
first
second
third
fourth
In an object oriented model, one object can access data of another object by passing?
Instance variable
Variable
Message
Function
Which of the following produces the relation that has attributes of R1 and R2
Cartesian product
Difference
Intersection
Product
What is the max data capacity of STP?
1 Gbps
56 Mbps
100 Mbps
256 Mbps
The index table has …… Columns.
1
2
3
4
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.
A subschema expresses
the logical view.
the physical view.
the external view.
all of the above.
The ________ states that a foreign key must either match a primary key value in another relation or it must be null.
entity integrity rule
referential integrity constraint
composite attribute
action assertion
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
The method of access which uses key transformation is known as
direct.
hash.
random.
sequential.
A composite attribute is converted to individual attributes in which of the following normal form ?
first
Second
third
fourth
Select the incorrect statement
View is derived from other tables.
Once a transaction has executed commit work its effect cant be undone by rollback work .
The input to the aggregate function avg can be non numeric data types
A primary key can never be null.
The minimal set of super key is called
Primary key
Secondary key
Candidate key
Foreign key