The exists construct returns the value true, if the argument subquery is
empty
nonempty
contains null values
none of the above
Correct Answer :
B. nonempty
Related Questions
The physical location of a record is determined by a mathematical formula that transforms
a file key into a record location is :
B-Tree File
Hashed File
Indexed File
Sequential file.
Tape storage is referred to as
sequential access storage
direct access storage
random access storage
none of the above
Electromagnetic spectrum included in radiowaves are
i) Super High Frequency (SHF)
ii) Very High Frequency (VHF)
iii) Ultra High Frequency (UHF)
iv) High Frequencies (HF)
i, ii and iii only
i, ii and iv only
ii, iii and iv only
i, iii and iv only
A data manipulation command the combines the records from one or more tables is called
SELECT
PROJECT
JOIN
PRODUCT
Which one of the following is provided by a data dictionary ?
User data
Database structure data
Sorted data
Functional data
A transaction which may not complete its execution successfully is termed as
Failed
Aborted
Blocked
Finished
Attenuation can be also expressed in decibel dB) and commonly used because.
i) Signal strengths often fall off logarithmically
ii) Cascade losses and gains can be calculated with simple additions and subtractions
i only
ii only
Both A and B
None of the above
The index table has …… Columns.
1
2
3
4
The syntax to select all column from the table is
select all from tablename
select * from tablename
select from tablename
none of these
The physical path over which a message travels
Thermal
Medium
Protocol
Impulse
The output of the Data Definition Language is stored in the
view table
schema
metadata
all of the above.
In case of entity integrity, the primary key may be
not Null
Null
both Null & not Null.
any value.
Which topology requires a central controller or hub?
Ring
Tree
Switch
Graph
Thermal noise is often referred to as ............... noise, because it affects uniformly the different frequencies.
Gray
White
Blue
Black
A functional dependency between two or more non-key attributes is called
Transitive dependency
Partial transitive dependency
Functional dependency
Partial functional dependency
An entity set that does not have sufficient attributes to form a primary key is a
strong entity set.
weak entity set.
simple entity set.
primary entity set.
Data stored in cursor is called ……………
record
active data set
object
none of the above
Which of the following aggregate function doesnt ignore NULLs in its results?
COUNT
COUNT(*)
MAX
none of these
In an Entity-Relationship Diagram Diamonds represents
Attributes
Multi-valued attributes
Weak entity set
Relationship sets
Which of the following Key is used to represent relationship between the tables?
Primary key
Secondary Key
Foreign Key
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
A composite attribute is converted to individual attributes in which of the following normal form ?
first
Second
third
fourth
Which of the following statements is not true about two tier client server database architecture?
SQL statements are processed on tier server
SQL statements may be processed on some of the clients
Business logic is mostly processed on clients
Business logic may be processed on the server
............... noise is caused by the random motion of the electrons in a wire and is avoidable.
Thermal
Intermodulation
Cross talk
Impulse
Symbol to represent weak entity set in ER Model
Dotted rectangle
Square
Doubly outlined rectangle
Diamond
Log into a computer across an internet
IMAP
TELNET
POP3
Infrared
DBMS utility which allows to reconstruct the correct state of database from the backup and history of transactions
Backup
Recovery
Grant
Troubleshooting
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
An association of several structure of a data base can be expressed graphically by?
Tuple
Record
Relationship
Field
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