Introduction to Database

Question 1

What is Database?

Answer 1

-Is a collection of data or information which is stored in a logical and structured way.

-“A shared collection of logically related data (along with a description of this data), designed to meet the information needs of an organisation”

-A single repository of data that can be used simultaneously by many departments and users

-As well as holding the organisation’s operational data, the database holds a description of this data. For this reason, a database is also defined as a self-describing collection of integrated records. The description of the data, that is the meta data is known as the system catalogue or data dictionary

Question 2

What is Database used for?

Answer 2

-To store
-To organise
-To manipulate data (adding, deleting, updating)

Question 3

Examples of non-computerised database:

Answer 3

-Dictionaries
-Telephone directories
-Address books

Question 4

Examples of computerised database

Answer 4

-Netflix
-Cellphone contacts
-Game library
-Amazon
-Facebook

Question 5

Common database applications

Answer 5

-Banking
-Airlines
-Universities
-Sales
-Manufacturing
-Human resources

Question 6

Some popular database software

Answer 6

-Oracle
-Microsoft SQL
-MySQL
-Microsoft Access

Question 7

Database software is sometimes called:

Answer 7

-Database manager
-Database management system (DBMS)

Question 8

Some of Data Models in DBMS

Answer 8

-Relational Model
-Hierarchical Model
-Object-Oriented Data Model

Question 9

Relational Database Model

Answer 9

-A data model attempts to represent the data requirements of the organisation (or some part)
-It should provide an integrated collection of concepts for: describing data, relationships between data and constraints on the data used by an organisation.
-Each line or row in a table is called a Record
-Each should have a unique field that is called Primary Key
-The Primary Key of one entity is the Foreign Key in another entity.

Question 10

Structural Components of Relational Models

Answer 10

-Field (Attribute)
-Record (Tuple)
-File (Relation)
-Domain
-Relational database

Question 11

Field

Answer 11

-Each of these (name, address, etc.) is one piece of information about you

-Each of these different types of information is called a “Field”

Question 12

Record

Answer 12

-All of the fields are put together to make a “record”

-A record is therefore all of the data about one person in a table

Question 13

File

Answer 13

-All of the records are stored together in a “file”

-A file consists of a collection of particular records

Question 14

Domains

Answer 14

-Every attribute in a relational database is associated with a domain

-It allows us to define the meaning and source of values that attributes can hold.

Question 15

A field or a collection of fields is designated as the __________ to provide uniqueness

Answer 15

Primary key

Question 16

A ______________ is a collection of tables that are related to one another based on a common field

Answer 16

Relational Database

Question 17

When the primary key of one table is represented in a second table to form a relationship, it is called

Answer 17

Foreign key

Question 18

What is Database Management System (DBMS)?

Answer 18

-Consists of programs that control the database structure and access to the data
-Information changes only have to be updated once
-A change only needs to be entered once and the information is updated in any relevant file

Question 19

Functions of DBMS

Answer 19

-Data storage, retrieval and update
-Concurrency control services
-Recovery services
-Security

Question 20

Data about data is normally termed as:

Answer 20

Metadata

Question 21

Table is synonymous with the term:

Answer 21

Relation

Question 22

Which of the following is true?
a. A relational table cannot have more than one column made of primary key
b. A relational table can have two columns made of primary key
c. A relational table may not have a primary key
d. b and c

Answer 22

c. A relational table may not have a primary key

Question 23

A property of the relational table is that:

Answer 23

Each column has a distinct name

Question 24

In a relational model, relationships between tables are created by using

Answer 24

Primary keys

Question 25

Primary key is equivalent to:
a. Master key
b. Private key
c. Key
d. Foreign key

Answer 25

c. Key

Question 26

A table with columns and rows is sometimes called

Answer 26

A relation

Question 27

Which of the following relates to referential integrity?
a. No column of a primary key can be null
b. A column can be currently unknown
c. Rules that define or constrain some aspect of the data used by the organization.
d. None of the above

Answer 27

a. No column of a primary key can be null

Question 28

_______states that primary keys should not be null

Answer 28

Entity Integrity

Question 29

A _____ is a shared collection of logically related data, designed to meet the information needs of an organisation.

Answer 29

Database

Question 30

DBMS stands for:

Answer 30

Database Management System

Question 31

Which of the following is an advantage of the DBMS?
a. Improves data integrity
b. Sharing of data
c. Improved data independence
d. All of the above

Answer 31

d. All of the above