Which of the following is logical topology?
Bus
Ring
Star
None of these
Correct Answer :
B. Ring
Related Questions
In an E-R diagram attributes are represented by
rectangle.
square.
ellipse.
triangle.
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
Only one communication channel is needed rather than n channels to transmit data between two communicating devices
parallel
serial
analog
digital
A subschema expresses
the logical view.
the physical view.
the external view.
all of the above.
A functional dependency between two or more non-key attributes is called
Transitive dependency
Partial transitive dependency
Functional dependency
Partial functional dependency
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
Select the correct
i) A timestamp-based scheduler cant produce live lock
ii) Aggregate functions cant appear with HAVING clause.
iii) Isolation is a property of database transaction.
i and ii only
ii and iii only
i and iii only
i only
In an Entity-Relationship Diagram Ellipses represents
Attributes
Weak entity set
Relationship sets
Multi-valued attributes
Size of source and destination address in IP header
4 bits
8 bits
12 bits
32 bits
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
Which of the following file organization provides very fast access to any arbitrary record of a file?
Ordered file
Unordered file
Hashed file
B-tree
Three SQL, DDL, CREATE commands are
Schema, Base and Table
Schema, Table and View
Base, Table and Schema
Key, Base and Table
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
Usenet is also known as
Newsgroups
10Km to 1Km
10^3Km to 100Km
100M to 10M
Relational Algebra is
Data Definition Language.
Data Manipulation Language
Procedural query Language
None of the above
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
The statement in SQL which allows to change the definition of a table is
Select
Update
Create
Alter
Natural mask for a Class A network
255.0.0.0
255.255.0.0
255.255.255.0
none of these
Cross Product is a:
Unary Operator
Binary Operator
Ternary Operator
none of the above
What is the result of the following SQL statement ?
SELECT A.emp_Name, B.ph_num
FROM emp A LEFT OUTER JOIN phone B
ON A. emp_ID = B.emp_ID
A list of employees phone number
A list of all employees that have spouses, with phone number included in the list
A list of all employees names, including the phone number if they have one
Two lists : One list of employees, the other of phone numbers
The output of the Data Definition Language is stored in the
view table
schema
metadata
all of the above.
Specialization is a
top-down approach.
bottom-up approach.
left-right approach.
none of the above
Which command is used to cancel privileges granted through the GRANT command ?
CANCEL
OVER
STOP
REVOKE
Tape storage is referred to as
sequential access storage
direct access storage
random access storage
none of the above
The language used in application programs to request data from the DBMS is referred to as the
DML
DDL
VDL
SDL
View never contains derived columns.
True
False
Cant say
none
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
What does a field or a combination of fields that has a unique value called ?
Foreign key
Secondary key
Primary key
Alternate key
In case of entity integrity, the primary key may be
not Null
Null
both Null & not Null.
any value.
Data integrity refers to
the uniqueness of the data in a database
the correctness and completeness of the data in a database
the un redundancies of the data in a database
Data independence of the database