Only one communication channel is needed rather than n channels to transmit data between two communicating devices
parallel
serial
analog
digital
Correct Answer :
B. serial
Related Questions
Which of the following Key is used to represent relationship between the tables?
Primary key
Secondary Key
Foreign Key
None of these
Which of the following is/are error-free channel(s)
i) Noisy channel
ii) Noiseless channel
i only
ii only
Both
None of these
In case of entity integrity, the primary key may be
not Null
Null
both Null & not Null.
any value.
Attenuation can be also expressed in decibel dB) and commonly used because.
i) Signal strengths often fall off logarithmically
ii) Cascade losses and gains can be calculated with simple additions and subtractions
i only
ii only
Both A and B
None of the above
Cross Product is a:
Unary Operator
Binary Operator
Ternary Operator
none of the above
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
The attribute that can be divided into other attributes is called
Simple Attribute
Composite Attribute
Multi-valued Attribute
Derived Attribute
Which of the following operator preserves unmatched rows of the relations being joined?
Inner join
Outer join
union
Intersect
The types of noiseless channels are
i) Selective Reject ARQ
ii) simplest protocol
iii) Go-Back-N ARQ
iv) Stop-and-Wait Protocol
i, ii only
ii and iv only
ii and iv only
i, iv only
DBMS utility which allows to reconstruct the correct state of database from the backup and history of transactions
Backup
Recovery
Grant
Troubleshooting
A logical description of some portion of database that is required by a user to perform task is called as
System View
User View
Logical View
Data View
Which of the following normalization is needed, if an attribute of a composite key is dependent on an attribute of the other composite key?
BCNF
Second
Third
Fourth
The minimal set of super key is called
Primary key
Secondary key
Candidate key
Foreign key
Which one of the following is provided by a data dictionary ?
User data
Database structure data
Sorted data
Functional data
Triggers are also called
active rules
passive rules
inferences
none of the above
Extended Entity Relationship model consists of which of the following
i) Specialization
ii) Generalization
iii) Categorization
i and ii only
ii and iii only
i and iii only
All i, ii iii
.................. means sending a digital signal over a channel without changing the digital signal to an analog signal.
Baseband transmission
Broadband transmission
Digital transmission
Analog transmission
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)
Three SQL, DDL, CREATE commands are
Schema, Base and Table
Schema, Table and View
Base, Table and Schema
Key, Base and Table
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.
Which command is used to cancel privileges granted through the GRANT command ?
CANCEL
OVER
STOP
REVOKE
In defining the notion of the tuple variable, which one of the clause is useful?
as
by
from
none of the above
Electromagnetic spectrum included in radiowaves are
i) Super High Frequency (SHF)
ii) Very High Frequency (VHF)
iii) Ultra High Frequency (UHF)
iv) High Frequencies (HF)
i, ii and iii only
i, ii and iv only
ii, iii and iv only
i, iii and iv only
Repeaters operate in
i) Physical layer
ii) Datalink layer
iii) Transport layer
iv) Network layer
i and ii only
ii and iii only
ii only
i only
Symbol to represent weak entity set in ER Model
Dotted rectangle
Square
Doubly outlined rectangle
Diamond
The overall design of a database is called
Subschema of the database
Schema of the database
Structure of the database
View of the database
Authorization command in SQL
Allow
Access
Grant
none of the above
The left outer join takes all tuples
in the left relation which didnt match with any tuple in right relation
in the left relation which matched with a tuple in right relation
in the right relation which didnt match with any tuple in left relation
in the right relation which matched with a tuple in left relation
Which of the following works as a filter?
UPDATE
DROP
ALTER
SELECT
For large networks, _______ topology is used
Ring
Bus
Mesh
none of these