Select the incorrect statement(s)
i) Foreign key values can be left blank
ii) In SQL duplicates may be present
iii) Theta join operation doesnt remove duplicate columns.
iv) NULL value means string of blank characters.
i ,iii only
ii, iv only
iii, iv only
ii, iii, iv
Correct Answer :
C. iii, iv only
Related Questions
Secondary storage
magnetic disk
magnetic tape
juke box
cache
A type of query that is placed within a WHERE or HAVING clause of another query is called
Super query
Sub query
Master query
Multi-query
Expand the acronym OLAP
Object Linked Access Program
Organizational Architecture Processing
Online Analytical Processing
none of these
Benefit of database normalization is
smaller number of tables
higher query processing efficiency
reduced I/O for most queries
reduced data redundancy
View never contains derived columns.
True
False
Cant say
none
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.
Database locking concept is used to solve the problem of
Lost Update
Uncommitted Dependency
Inconsistent Data
All of the above
The access protocol used by traditional Ethernet
CSMA/CA
CSMA/CD
CSMA
Token ring
Natural mask for a Class A network
255.0.0.0
255.255.0.0
255.255.255.0
none of these
Which of the following layer uses trailer of the frame for error detection?
Transport layer
Network layer
Datalink layer
None of these
A functional dependency between two or more non-key attributes is called
Transitive dependency
Partial transitive dependency
Functional dependency
Partial functional dependency
In ………… paging we make copy of the current page table.
physical
logical
shadow
duplicate
Which of the following is not a constraint on a single relation?
check
unique
not null
is duplicate
Select the incorrect statement(s)
i) Shared locks are compatible with each other.
ii) A relation which is in 3NF may have redundancy due to composite keys.
iii) A table in a database can have multiple indexes.
i only
ii, only
ii, iii only
none of the above
The class based addressing is known as
Classless addressing
Classful addressing
Classified addressing
Classical addressing
Size of source and destination address in IP header
4 bits
8 bits
12 bits
32 bits
The minimal set of super key is called
Primary key
Secondary key
Candidate key
Foreign key
Event condition action model is related to
Views
Cursors
Triggers
None of these.
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
An entity set which have sufficient attributes to form a primary key
Tree structure
Subtree structure
Strong entity set
Table structure
The host part in a class A type of an IP address has
12 bits
16 bits
24 bits
28 bits
UML is stands for
Universal Modeling Language
Unified Modeling Language
United Modeling Language
Uni Modeling Language
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
The database environment has all of the following components except:
users.
separate files.
database.
database administrator.
Related fields in a database are grouped to form a
data file.
data record.
menu.
bank.
Which of the following is also known as Offline storage ?
primary storage
secondary storage
tertiary storage
none of the above
Which of the following is not a database object?
index
sequence
cursor
trigger
A data dictionary contains:
i) The name of all fields in all files.
ii) The data type of all fields in all files.
iii) The width of all fields in all files.
only i)
only i) and ii)
only ii) and iii)
i) ii) iii)
In which of the random-access method, stations do not sense the medium?
ALOHA
ETHERNET
CSMA/CA
CSMA/CD
In client/server computing data are
sent only upon the client's request
sent in complete copies for the client to filter and sort
never sent to the client machine
sent in very large sections to save processing time