Datbase System Exam 1

Quizes

Application programs

To allow users to manipulate the information, the system has a number of

Network Maintenance

Which of the following in not a function of DBA?

Programs are not dependent on the physical and logical attributes of data

Data independence means

Attribute

A characteristic of an entity.

End Users

DBMS manages the interaction between __________ and database.

Network Model

Which of the following is a navigational data model model?

Retrieval of information stored in database
Insertion of new information into the database
Deletion of information from the database

Data Manipulation Language enables users to

alter

____ command can be used to modify a column in a table

Create information table in the Database

Data Manipulation Language (DML) is not to

logical

A level that describes data stored in a database and the relationships among the data.

Schema

A logical structure of the database.

Database Schema

Logical design of database is called

Physical

A level that describes how a record is stored.

Programs

DBMS is a set of __________ to access the data.

Geographic information systems (G I S)

Can store and analyze maps, weather data, and satellite images.

Data independence and Centralized control of data

DBMS helps achieve

DDL, DML and DQL

Which of the following is Database Language?

schema

A ……… is used to define overall design of the database

File processing system

Data redundancy and Data Inconsistency is one of the major drawbacks of

Call the DBMS to access the stored data

Database processing programs:

Database designers

_____ are considered database architects.

Instance

The actual content in the database at a particular point.

database warehouse

A ____ focuses primarily on storing data used to generate information required to make tactical or strategic decisions.

Data Model

A type of data abstraction that is used to provide a conceptual representation

DBMS system designers and implementors

They design and implement the DBMS modules and interfaces as a software package

True

T/F A data model is a graphical system used to capture the nature and relationships among data.

user

Which of the following isn't a level of abstraction?

Data is separated and isolated
Data is often duplicated
Application programs are dependent on file format

File processing systems have important limitations

view

The ______level helps application programs hide the details of data types.

HTML

Which of the following is not involved in DBMS?

Critical Level

Which of the following is not a level of data abstraction?

Conceptual

A(n) ____ model is independent of both hardware and software.

Stringent real-time requirements

It is better to use files than a DBMS when there are

redundancy

Data ____ exists when the same data are stored unnecessarily at different places.

Constraint

The restrictions placed on the data.

tree structure

The hierarchical database model is based on a ____.

It is an integrated collection of logically related records.
It consolidates separate files into a common pool of data records
Data stored in a database is independent of the application programs using it

The property / properties of a database is / are

Database Instance

Snapshot of the data in the database at a given instant of time is called

False

T/F With the traditional file processing approach, each application shares data files, thus enabling much data sharing.

Meta Data
Collection of programs to access data
Collection of interrelated data

A Database System is:

insert into R1
Delete from R2

Let R1(A, B, C, D) and R2(P, Q, R, S) be two relations in which A is the foreign key of R1 that refers to the primary key of R2. Which of the following operations causes the referential integrity constraint violation?

Primary key values cannot be null according to the entity integrity constraint.

What is TRUE about Entity Integrity Constraints?

True

T/F An entity instance of a subtype represents the same entity instance of the supertype.

supertypes

In a supertype/subtype hierarchy, subtypes that are lower in the hierarchy inherit attributes from not only their immediate supertype but from all ________ in the hierarchy.

completeness

A(n) ________ constraint is a type of constraint that addresses whether an instance of a supertype must also be an instance of at least one subtype.

predicate-defined subclass

The kind of subclass on which the entity become part of subclass by putting some condition on attribute values is classified as

identifying relationship

A(n) ________ is the relationship between a weak entity type and its owner

Snapshot

Thus a _______ of course data gives the values of all attributes, such as title and department, of all courses at a particular point in time.

Supertype

Which of the following is a generic entity type that has a relationship with one or more subtypes?

Instance

What term is used to refer to a specific record in your music database; for instance; information stored about a specific album?

False

T/F ERM is an acronym for Enterprise Reliability Model.

disjoint

The ________ rule specifies that an entity can be a member of only one subtype at a time.

Total specialization

Which of the following is a completeness constraint?

partial specialization

The ________ rule specifies that an entity instance of a supertype is allowed not to belong to any subtype.

derived attribute.

An attribute of an entity that is computed is a(n):

Recursive relationships

Relationships among entities of the same type are called_______?

mandatory

A relationship where the minimum and maximum cardinality are both one is a(n) ________ relationship.

Belong to the same entity class
Have the same attributes

All instances of a given entity?

False

T/F In an entity called STUDENT, you might find attributes of PROFESSOR-ID, Last-Name, First-Name and CLASSROOM.

there are attributes that apply to some but not all instances of an entity type.

Subtypes should be used when:

identify the entities

The first step to building an Entity Relationship Diagram is to _____

subtype discriminator.

An attribute of the supertype that determines the target subtype(s) is called the:

Relationship, attribute, entity

The three major parts of an ERM diagram are:

any

The Tuples of the relations can be of ____ order.

No proper subset is a super key

The subset of super key is a candidate key under what condition?

indivisible

A domain is atomic if elements of the domain are considered to be ______ units.

False

T/F The relationship among the instances of three entity types is called a unary relationship.

partial specialization

The rule specifies that an entity instance of a supertype is allowed not to belong to any subtype.

False

T/F In entity-relationship models, a member of a subtype does NOT necessarily have to be a member of the supertype.

Referential integrity

Which data modeling concept ensures that every relationship is supported by accurate and existing data?

both true

Which of the following statements are true:

1. Each superkey is a superset of some candidate key,

2. Each primary key is also a candidate key, but there may be candidate keys that are not primary keys).

False

T/F At most 2 distinct entity sets can be associated with any relationship set R.

There is no significance to attribute domains

Which of the following is FALSE about the properties of relations?

Candidate keys

In relational database minimal superkeys is known as:

Physical Data Modeling

Which data modeling stage involves transforming the logical data model into a database-specific schema?

associative entity

relationships modeled as an entity type. 

attribute 

property of an entity.

entity

person, place, object, concept, event.

relationship type

association between entity types.

data

facts, text, graphics, images, etc

cardinality constraint 

specifies maximum and minimum number of instances.

supertype

generalized entity type. 

uniquely identifies entity instances.

identifier

overlap rule

an entity belongs to two subtypes

specialization 

creating subtypes for an entity type