A table can have only one
Secondary key
Alternate key
Unique key
Primary key
Correct Answer :
D. Primary key
Related Questions
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
An advantage of views is
Data security
Derived columns
Hiding of complex queries
All of the above
The normal form that is not necessarily dependency preserving is
2NF
3NF
BCNF
4NF
Relationships among relationships can be represented in an-E-R model using
Aggregation
Association
Weak entity sets
Weak relationship sets
Employees in a company are each assigned their own office, i.e. for each employee there exists a unique office and for each office there exists a unique employee; This statement is an example of ____ type of relation.
1:1
1: Many
Many: One
Many : Many
What are the desirable properties of a decomposition
Partition constraint.
Dependency preservation.
Redundancy.
Security.
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
Drop Table cannot be used to drop a table referenced by a ______ constraint.
Primary Key
Local Key
Foreign Key
Composite Key
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
The default level of consistency in SQL is
repeatable read
read committed
read uncommitted
serializable
The data in the database at a particular moment of time is called the _______
Snapshot
Dynaset
Stateless
Stateful
A top-to-bottom relationship among the items in a database is established by a
Hierarchical schema
Network schema
Relational Schema
All of the above
The transactions like adding an employee, enrolling a student in a course are examples of _______
Logical
Physical
None
Theoretical
Which of the following is not comparison operator?
<>
<
=<
>=
………………… approach reduces time and effort required for design and lesser risk in database management.
Single global database
Multiple databases
Top-down approach
None of the above
The common column is eliminated in
theta join
outer join
natural join
composed join
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.
DBMS helps achieve
Centralized control of data
Data independence
Both A and B
Neither A nor B
If a transaction T has obtained an exclusive lock on item Q, then T can
read Q
write Q
both read and write Q
write Q but not read Q
In b-tree the number of keys in each node is than the number of its children.
one less
same
one more
half
The ______ key of a relation is the attribute (column) or collection of attributes, which uniquely identify a given tuple.
Primary
Foreign
Candidate
Alternate
Data items grouped together for storage purposes are called a
record
string
title
list
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
The part of a database management system which ensures that the data remains in a consistent state is
authorization and integrity manager
buffer manager
transaction manager
file manager
Which of the following aggregate functions does not ignore nulls in its results?.
COUNT .
COUNT (*)
MAX
MIN
A relation is in attribute of other composite key. if an attribute of a composite key is dependent on an
2NF
3NF
BCNF
1NF
SQL server stores index information in the _____system table
system indexes
syst indexes
sys indexes
sysind
Protection of data from unauthorized Disclosure results in loss of _______
Integrity
Availability
Confidentiality
Discretionary Security
Which of the following is not a property of transactions?
Atomicity
Concurrency
Isolation
Durability
A DBMS is a ____ user if at most one user can use the system and is mostly restricted to personal computer systems.
None
Multi
Single
Concurrent