The command used to delete a particular column in a relation
UPDATE
DROP
ALTER
DELETE
Correct Answer :
C. ALTER
Related Questions
Consider the join of a relation R with relation S. If R has m tuples and S has n tuples,
then the maximum size of join is:
mn
m+n
m+n)/2
2 m+n)
Which of the following works as a filter?
UPDATE
DROP
ALTER
SELECT
Range variables are designed using the
TO clause
FROM clause
RANGE clause
none of the above
In a Hierarchical model records are organized as
Graph.
List.
Links.
Tree.
Object based data models are used in describing the abstraction of the following levels?
Conceptual and view
Only physical
Physical and conceptual
Only conceptual
Tape storage is referred to as
sequential access storage
direct access storage
random access storage
none of the above
Relational Algebra is
Data Definition Language.
Data Manipulation Language
Procedural query Language
None of the above
Which of the following is also known as Offline storage ?
primary storage
secondary storage
tertiary storage
none of the above
Which of the following Key is used to represent relationship between the tables?
Primary key
Secondary Key
Foreign Key
None of these
The raw facts and figures are:
Data
Data field
DBMS
DBASE
Aggregate functions are also called
serial functions
non-serial functions
row functions
column functions
File organization that provides fast access to any arbitrary record
Hashed file
B-tree
Ordered file
Unordered file
In E-R diagram Generalization is represented by
Circle
Rectangle
Hyperbola
Triangle
In two-phase locking
the data items are locked in growing phase.
the data items are released in shrinking phase.
Both A and B are true
Both A and B are false
Expand the acronym OLAP
Object Linked Access Program
Organizational Architecture Processing
Online Analytical Processing
none of these
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
Event condition action model is related to
Views
Cursors
Triggers
None of these.
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
Symbol to represent weak entity set in ER Model
Dotted rectangle
Square
Doubly outlined rectangle
Diamond
.................. is the loss of energy as the signal propagates outward, where the amount of energy depends on the frequency.
Noise
Delay distortion
Attenuation distortion
Dispersion
What is the max data capacity of STP?
1 Gbps
56 Mbps
100 Mbps
256 Mbps
Data fragmentation is performed by the …… and each fragment is stored at…………..
DBMS, same site
OS ,same site
DBMS ,different site
OS ,different site
QBE
Query By Execution
Query By Example
Query By Extraction
None of the above.
An advantage of the database management approach is
data is dependent on programs.
data redundancy increases.
data is integrated and can be accessed by multiple programs.
none of the above.
Which of the following produces the relation that has attributes of R1 and R2
Cartesian product
Difference
Intersection
Product
The exists construct returns the value true, if the argument subquery is
empty
nonempty
contains null values
none of the above
An association of several structure of a data base can be expressed graphically by?
Tuple
Record
Relationship
Field
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
The number of cursors depend on the
number of queries
number of attributes
size of memory area
none of these
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