It is an abstraction through which relationships are treated as higher level entities
Generalization.
Specialization.
Aggregation.
Inheritance.
Correct Answer :
C. Aggregation.
It is an abstraction through which relationships are treated as higher level entities Aggregation. (In ER diagram, aggregation is used to represent a relationship as an entity set.)
Related Questions
Which of the following ensures the atomicity of the transaction?
Transaction management component of DBMS
Application Programmer
Concurrency control component of DBMS
Recovery management component of DBMS
The ______ language consists of SQL statements for operating on the data (insert, Modify, Delete) in tables that already exist.
Data Manipulation
Data Definition
Data Control
None
The normal form that is not necessarily dependency preserving is
2NF
3NF
BCNF
4NF
The division operator divides a dividend A of degree m+n by a divisor relation B of degree n and produces a result of degree
m - 1
m + 1
m * m
m
Consider the join of relation R with a relation S. If R has m tuples and S has n tuples, then the maximum and minimum size of the join respectively are
m+n and 0
m+n and |m-n|
mn and 0
mn and m+n
Which one is true statement :
With finer degree of granularity of locking a high degree of concurrency is possible.
Locking prevents non-serializable schedules.
Locking cannot take place at field level.
An exclusive lock on data item X is granted even if a shared lock is already held on X.
A transaction is in state after the final statement has been executed.
partially committed
active
committed
none of the above
Change Staff table by removing default of Assistant for position column
ALTER TABLE Staff ALTER position DROP DEFAULT;
ALTER TABLE Staff ALTER position DEFAULT;
ALTER TABLE Staff ALTER DROP DEFAULT;
MODIFY Staff ALTER position DROP DEFAULT;
The set of all values that can be taken by the attribute is called as _______ of the attribute.
Tuple
Cardinality
Degree
Domain
If an entity can belong to only one lower level entity then the constraint is
disjoint
partial
overlapping
single
Tree structures are used to store data in
Network model.
Relational model.
Hierarchical model.
File based system.
In SQL the word natural can be used with
inner join
full outer join
right outer join
all of the above
Data items grouped together for storage purposes are called a
record
string
title
list
Which of the following is not comparison operator?
<>
<
=<
>=
The values of the attribute describes a particular
Entity set
File
Entity instance
Organization
A relational database developer refers to a record as
an attribute
a tuple
a criteria
a relation
In multiple granularity of locks SIX lock is compatible with
IX
IS
S
SIX
_____ database is used to provide statistical information or summaries of values based on various criteria.
Statistical
Mathematical
Normalized
Un normalized
Which of the following is not a logical database structure?
Chain
Network
Tree
Relational
An advantage of views is
Data security
Derived columns
Hiding of complex queries
All of the above
The transactions like adding an employee, enrolling a student in a course are examples of _______
Logical
Physical
None
Theoretical
Which two files are used during operation of the DBMS?
Query languages and utilities
DML and query language
Data dictionary and transaction log
Data dictionary and query language
What is data integrity?
It is the data contained in database that is non redundant.
It is the data contained in database that is accurate and consistent.
It is the data contained in database that is secured.
It is the data contained in database that is shared.
Manager salary details are hidden from the employee .This is
Conceptual level data hiding.
External level data hiding.
Physical level data hiding.
None of these.
Checkpoints are a part of
Recovery measures.
Security measures.
Concurrency measures.
uthorization measures.
If both the functional dependencies : X�Y and Y�X hold for two attributes X and Y then the relationship between X and Y is
M:N
M:1
1:M
According to the levels of abstraction, the schema at the intermediate level is called
Logical schema.
Physical schema.
Subschema.
None of the above.
The _____ category includes storage media that can be operated on directly by the computers central processing unit.
Primary storage
Secondary Storage
All
Tertiary Storage
Dependency preservation is not guaranteed in
BCNF
3NF
PJNF
DKNF
The data models defined by ANSI/SPARC architecture are
Conceptual, physical and internal
Conceptual, view and external
Logical, physical and internal
Logical, physical and view