Database Exam 1

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Entity

A real world identifiable object

Entity set

Collection of similar entities

relationship set

Collection of similar relationships

Explain Relation-based tables characteristic of a DBMS

DBMS allows entities and relations around them to form tables

Explain query language of a DBMS as a characteristic of a DBMS

DBMS contains query language which helps get and manipulate data

Explain Multiuser and Concurrent Access as a characteristic of a DBMS

DBMS supports multiusers and allows parallel data access.

While formulating real-world scenario into the database model, the ER Model creates all of the following EXCEPT?

Data

ER model

Defines the conceptual view of the database

One-to-one

Each entity in the relationship will have exactly one related entity

Explain Multiple views as a characteristic of a DBMS

Enables users to have a concentrated view of the database to their specifications

The user(presentation) tier

End-users operate on this tier

Many-to-many

Entities on both sides of the relationship can have many related entities on the other side

Which of the following is NOT true regarding 2-tier architecture?

It is the most widely used architecture to design a DBMS

Designer user type

People the work on designing the database

Attributes

Properties that represent an entity that has values

Explain the Administrators user type

Responsible to look after usage and who should use the dbms

What does NOT define a data model

Stored in a flat file

Explain Security as a characteristic of a DBMS

This enables multiple users to have different views and different features.

End users user type

Those who actually use the database

Entity-Relationship (ER) Model is based on the notion of real-world entities and relationships among them.

True

Multi-value attributes may contain multiple values, such as tow or more phone numbers or email addresses.

True

Single-value attributes contain single value.

True

Tuples are known as records

True

Which of the following is NOT part of the 3-tier Architecture?

View tier

Explain consistency characteristic of a DBMS

Where the relations remain consistent

Explain Isolation of data and application characteristic of a DBMS

a database is an active entity where data is said to be passive.

Describe logical data independence?

a kind of mechanism, which liberalizes itself from actual data changes on table format should not change the data residing on the disk

Entity

a real world object

Which of the following describe a database instance?

a state of operational database with data at any given time contains a snapshot of the database

Which is not a valid mapping cardinality?

all to all

The database (data) tier

at this tier the database resides along with its query processing languages

Simple attribute

atomic values that cannot be further divided

Definition of a dbms

collection interrelated data

Definition of a database

collection of related data

domain

data type

Explain Less redundancy characteristic of a DBMS

dbms follows the rules of normalization

Which of the following describes the Physical Database Schema?

defines how the data will be stored in a secondary storage pertains to the actual storage of data and its form of storage like files, indices, etc

Which of the following describes the Logical Database Schema?

defines tables, views, and integrity constraints defines all the logical constraints that need to be applied on the data stored

mapping cardinalities

defines the number of assoication between two entities

Which of the following describe a database schema?

is the skeleton structure that represents the logical view of the entire database defines its entities and the relationship among them defines how the data is organized

Which of the following is NOT true regarding 1-tier architecture?

it must have an application through which the DBMS can be accessed

Describe logical data

it stores information about how data is managed inside data about database

relationship

logical association among entities

Candidate key

minimal super key

Real-world entity characteristic

modern dbms are realistic and uses real-world entities to design its architecture

Degree of relationship

number of participating entities in a relationship

Primary Key

one of the candidate keys

attribute

property or characteristic

Definition of data

represents recordable facts

Super key

set of attribute that identifies an entity

The application(middle) tier

the application server and the programs that access the database reside on this tier

Attributes are known as columns

true

tables are known as relations

true

One-to-many

An entity on one side of the relationship can have many related entities, but an entity on the other side will have a maximum of one related entity

relationship

Association between entities

Explain ACID properties as a characteristic of a DBMS

Atomicity, Consistency, Isolation, Durability.

Composite attributes

Attributes that consist of multiple simple attributes

Derived attributes

Attributes that do not exist in the database but their values are derived from other attributes


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