The ________ states that a foreign key must either match a primary key value in another relation or it must be null.
entity integrity rule
referential integrity constraint
composite attribute
action assertion
Correct Answer :
A. entity integrity rule
Related Questions
The collection of information stored in a database at a particular moment is?
View
Instance
Scheme
None of these
…………… is responsible for using that the database remains in a consistent state despite system failure.
Storage manager
Admin
Transaction manager
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.
The ________ states that a foreign key must either match a primary key value in another relation or it must be null.
entity integrity rule
referential integrity constraint
composite attribute
action assertion
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
DBMS utility which allows to reconstruct the correct state of database from the backup and history of transactions
Backup
Recovery
Grant
Troubleshooting
Which of the following operator preserves unmatched rows of the relations being joined?
Inner join
Outer join
union
Intersect
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
Which command is used to cancel privileges granted through the GRANT command ?
CANCEL
OVER
STOP
REVOKE
Authorization command in SQL
Allow
Access
Grant
none of the above
The union of primary keys of a related entity becomes …………. Of a relation.
primarykey
superkey
candidatekey
foreignkey
Noiseless channel has ……… types of protocols.
2
3
4
5
The class based addressing is known as
Classless addressing
Classful addressing
Classified addressing
Classical addressing
A lock that allows concurrent transactions to access different rows of the same table is known as a
Field-level lock
Row-level lock
Table-level lock
Database-level lock
The exists construct returns the value true, if the argument subquery is
empty
nonempty
contains null values
none of the above
Datalog is
procedural query language
nonprocedural query language
scan(), write()
none of the above
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)
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
Which of the following are the properties of entities?
Groups
Table
Attributes
Switchboards
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
Symbol to represent weak entity set in ER Model
Dotted rectangle
Square
Doubly outlined rectangle
Diamond
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
Technique used in log based recovery
Immediate database modification
Graph-based recovery
key dependencies
none of the above
Which topology requires a central controller or hub?
Ring
Tree
Switch
Graph
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 command used to delete a particular column in a relation
UPDATE
DROP
ALTER
DELETE
A logical description of some portion of database that is required by a user to perform task is called as
System View
User View
Logical View
Data View
A transaction which completes successfully is called
Granted
Committed
Compensated
Accomplished
Data independence means
data is defined separately and not included in programs.
programs are not dependent on the physical attributes of data.
programs are not dependent on the logical attributes of data.
both B) and C).
RAID
Redundant Arrays of Independent Disks
Redundant Arrays of Independent Drives
Redundant Arrays of Interconnected Drives
Redundant Arrays of Interconnected Disks