Database Concepts Exam 1

Real World Entity

A modern DBMS is more realistic uses real world entities to design its architecture

Attribute

A property or characteristic of an entity that has values

Which of the following describe logical data independence? Select all that apply. A) changes on table format should not change the data residing on the disk B) a kind of mechanism, which liberalizes itself from actual data C) Data about database D) it stores information about how data is managed inside

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

Application (Middle) Tier

At this tier reside the application and the programs that access the database

ACID Properties

Atomicity, Consistency, Isolation, Durability

Which of the following describe a database instance? Select all that apply A) does not contain any data or information B) a state of operational database with data at any given time C) contains a snapshot of the database D) the skeleton of database

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

Which of the following describe logical data? Select all that apply. A) changes on table format should not change the data residing on the disk B) data about database C) a kind of mechanism, which liberalizes itself from actual data D) it stores information about how data is managed inside

B) data about database D) it stores information about how data is managed inside

Which of the following describes the Logical Database Schema? Select all that apply. A) defines how the data will be stored in a secondary storage B) defines all the logical constraints that need to be applied on the data stored C) defines tables, views, and integrity constraints D) pertains to the actual storage of data and its form of storage like files, indices, etc

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

Which of the following describe a database schema? Select all that apply. A) contains a snapshot of the database B) defines how the data is organized C) is the skeleton structure that represents the logical view of the entire database D) DBMS ensures that its every instance (state) is in a valid state E) defines its entities and the relationship among them

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

Which of the following describes the Physical Database Schema? Select all that apply. A) defines tables, views, and integrity constraints B) pertains to the actual storage of data and its form of storage like files, indices, etc C) defines all the logical constraints that need to be applied on the data stored D) defines how the data will be stored in a secondary storage

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

Consistency

Consistency is a state where every relation in a database remains constant

Relation-based tables

DBMS allows entities and relations among them to form tables

Less redundancy

DBMS follows the rules of normalization, which splits a relation when any of its attributes is having redundancy in values

Query Language

DBMS is equipped with query language, which makes it more efficient to retrieve and manipulate data

Multiuser and Concurrent Access

DBMS supports multi-user environment and allows them to access and manipulate data in parallel

While formulating real-world scenario into the database model, the ER Model creates all of the following EXCEPT? <relationship set, general attributes, data, constraints, entity set>

Data

User (Presentation) Tier

End-users operate on this tier

Designers

Group of people who actually work on the designing part of the database

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

It is the most widely used architecture to design a DBMS

Many-to-one

More than one entities from entity set A can be associated with at most one entity of entity set B

Degree of relationship

Number of participating entities in a relationship

Many-to-many

One entity from A can be associated with more than one entity from B and vice versa

One-to-many

One entity from entity set A can be associated with more than one entities of entity set B however an entity from entity

Primary Key

One of the candidate keys

Entity

Real-world object that is identifiable

Data

Represents recordable facts

Super Key

Set of attributes that collectively identifies an entity

Which of the following does NOT define a data model?

Stored in a flat file

Database (Data) Tier

The database resides along with its query processing languages.

Multiple views

This feature enables the users to have a concentrate view of the database according to their requirements.

End Users

Those who actually reap the benefits of having a DBMS

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

True

In the Relational Model attributes are also known as columns. (True or False)

True

In the Relational Model tables are also know as relations. (True or False)

True

In the Relational Model tuples are also known as records. (True or False)

True

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

True

Single-value attributes contain single value. (True or False)

True

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

View tier

Database Management Systems (DBMS)

a collection of interrelated data

entity set

a collection of similar types of entities

Isolation of data and application

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

Which of the following is NOT a valid mapping cardinality? <One to many, all to all, many to one, many to many, one to one>

all to all

Composite attribute

are made of more than one simple attribute

Simple attribute

atomic values, which cannot be divided further

Derived attribute

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

Database

collection of related data

Domain

data type

Mapping Cardinalities

define the number of association between the two entities

ER Model

defines the conceptual view of a database

Security

enables multiple users to have different views with different features

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

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

Relationship

logical association among entities

Candidate Key

minimal super key

One-to-one

one entity from set A can be associated with at most one entity of entity set B and vice versa

Relationship Set

set of relationships of similar type

administrators

they are responsible to look after its usage and by whom it should be used