Object based data models are used in describing the abstraction of the following levels?
Conceptual and view
Only physical
Physical and conceptual
Only conceptual
Correct Answer :
A. Conceptual and view
Related Questions
The overall design of a database is called
Subschema of the database
Schema of the database
Structure of the database
View of the database
Only one communication channel is needed rather than n channels to transmit data between two communicating devices
parallel
serial
analog
digital
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
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
What does the number of attributes in a relation is called?
Cardinality
Degree
Tuple
Order
A transaction is said to have terminated if it has
either committed or aborted
either partially committed or aborted
either committed or failed
none of these
A composite attribute is converted to individual attributes in which of the following normal form ?
first
Second
third
fourth
Which of the following is logical topology?
Bus
Ring
Star
None of these
Datalog is
procedural query language
nonprocedural query language
scan(), write()
none of the above
QBE
Query By Execution
Query By Example
Query By Extraction
None of the above.
Aggregate functions are also called
serial functions
non-serial functions
row functions
column functions
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)
In this data model each record can hae more than one parent
Hierarchical model
E-R model
Network based model
none of these
Tape storage is referred to as
sequential access storage
direct access storage
random access storage
none of the above
It is possible to define a schema completely using
VDL and DDL.
DDL and DML.
SDL and DDL.
VDL and DML.
Triggers are also called
active rules
passive rules
inferences
none of the above
Noiseless channel has ……… types of protocols.
2
3
4
5
A transaction which completes successfully is called
Granted
Committed
Compensated
Accomplished
In mesh topology, if the number of devices is n , then the number of ports present in each device is
n
n+1
n-1
n/2
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
Functional dependencies are generalization of
Relation dependencies
Data dependencies
key dependencies
none of the above
In RDBMS, Data is presented as a collection of
Relation
Table
Attribute
Entity
Which of the following is not a database object?
index
sequence
cursor
trigger
The syntax to select all column from the table is
select all from tablename
select * from tablename
select from tablename
none of these
EEPROM
Electrically Extractable Programmable Read Only Memory
Electrically Erasable Programmable Read Only Memory
Electronically Erasable Programmable Read Only Memory
Electrically Erasable Programmable Read Only Memory
.................. 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
The class based addressing is known as
Classless addressing
Classful addressing
Classified addressing
Classical addressing
Which of the following layer uses trailer of the frame for error detection?
Transport layer
Network layer
Datalink layer
None of these
The statement in SQL which allows to change the definition of a table is
Select
Update
Create
Alter
A …………… is a memory area where data are processed.
view
trigger
cursor
none of the above