A subschema expresses
the logical view.
the physical view.
the external view.
all of the above.
Correct Answer :
C. the external view.
Related Questions
In an object oriented model, one object can access data of another object by passing?
Instance variable
Variable
Message
Function
The attribute that can be divided into other attributes is called
Simple Attribute
Composite Attribute
Multi-valued Attribute
Derived Attribute
Technique used in log based recovery
Immediate database modification
Graph-based recovery
key dependencies
none of the above
In an Entity-Relationship Diagram Diamonds represents
Attributes
Multi-valued attributes
Weak entity set
Relationship sets
.................. 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
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
The minimal set of super key is called
Primary key
Secondary key
Candidate key
Foreign key
Benefit of database normalization is
smaller number of tables
higher query processing efficiency
reduced I/O for most queries
reduced data redundancy
In two-phase locking protocol the two phases are
growing phase and shrinking phase
execution phase and blocking phase.
running phase and sleeping phase.
none of the above
Range variables are designed using the
TO clause
FROM clause
RANGE clause
none of the above
A lock that allows concurrent transactions to access different rows of the same table is known as a
Field-level lock
Row-level lock
Table-level lock
Database-level lock
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 by which the structure of the database is modified to eliminate hidden dependencies and replacing groups is
Normalization
Indexing
Enforcing referential integrity
Enforcing data integrity
Which of the following is a classical approach to database design?
Left Right approach
Right Left approach
Top Down approach
Bottom Up approach
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
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.
DECLARE is a(an)
executable statement.
declarative statement.
Ordered file
none of the above
Log into a computer across an internet
IMAP
TELNET
POP3
Infrared
Which of the following works as a filter?
UPDATE
DROP
ALTER
SELECT
The raw facts and figures are:
Data
Data field
DBMS
DBASE
A composite attribute is converted to individual attributes in which of the following normal form ?
first
Second
third
fourth
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
Which of the following produces the relation that has attributes of R1 and R2
Cartesian product
Difference
Intersection
Product
The control of concurrent execution is left with the
operating system
controller unit of the kernel
concurrency control component of the database system
none
The transaction consists of all statements executed between
the begin transaction and end transaction
the start transaction and end transaction
the begin transaction and finish transaction
none of the above.
Multivalued dependency is removed in
4 NF
3 NF
2 NF
1 NF
Datalog is
procedural query language
nonprocedural query language
scan(), write()
none of the above
Event condition action model is related to
Views
Cursors
Triggers
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
Only one communication channel is needed rather than n channels to transmit data between two communicating devices
parallel
serial
analog
digital